Editing Amazon River

{{Short description|Major river in South America}}
{{Use dmy dates|date=February 2020}}
{{Infobox river
| name = Amazon River
| native_name = {{native name|pt|Amazonas}}
| name_other = {{lang|pt|Rio Amazonas}}, {{lang|es|Río Amazonas}}
| image = Amazon River ESA387332.jpg
| image_size = 250
| image_caption = Satellite image of the [[Amazon Delta]]
| map = Amazonrivermap.svg
| map_size = 250
| map_caption = Amazon River and [[Amazon basin|its drainage basin]]
| pushpin_map = 
| pushpin_map_size = 250
| pushpin_map_caption = 
| subdivision_type1 = Country
| subdivision_name1 = [[Peru]], [[Colombia]], [[Brazil]]
| subdivision_type2 = 
| subdivision_name2 = 
| subdivision_type3 = 
| subdivision_name3 = 
| subdivision_type4 = 
| subdivision_name4 = 
| subdivision_type5 = Cities
| subdivision_name5 = [[Iquitos]] (Peru); [[Leticia, Amazonas|Leticia]] (Colombia);<br /> [[Tabatinga]] (Brazil); [[Tefé]] (Brazil);<br /> [[Itacoatiara, Amazonas|Itacoatiara]] (Brazil) [[Parintins]] (Brazil);<br /> [[Óbidos, Pará|Óbidos]] (Brazil); [[Santarém, Pará|Santarém]] (Brazil);<br /> [[Almeirim, Pará|Almeirim]] (Brazil); [[Macapá]] (Brazil);<br />[[Manaus]] (Brazil)
| length = {{cvt|3,750|km|mi|abbr=on}}<ref name="The Amazon River">{{cite web|url=https://en.aguasamazonicas.org/basins/amazon-main-stem/the-main-stem|title=The Amazon River|date=28 May 2014 }}</ref>
(''Amazon–Ucayali–Tambo–Ené–Apurímac'' {{cvt|6,400-6,500|km|mi|abbr=on}}{{refn|name=length|group=n|The length of the Amazon River is usually said to be "at least" {{cvt|6,400|km|sp=us}},<ref name=britannica-amazon>{{cite encyclopedia |url=https://www.britannica.com/place/Amazon-River |title=Amazon River |encyclopedia=Encyclopædia Britannica |url-status=live |archive-url=https://web.archive.org/web/20201108222644/https://www.britannica.com/place/Amazon-River |archive-date=8 November 2020}}</ref> but reported values lie anywhere between {{cvt|6275|and|7025|km|sp=us}}.<ref name=liu-etal-river-length/>
The length measurements of many rivers are only approximations and differ from each other because many factors determine the calculated river length, such as the position of the geographical source and the mouth, the scale of measurement, and the length measuring techniques (for details see also [[List of rivers by length]]).<ref name=liu-etal-river-length/><ref name=river-source>{{Cite web |url=https://news.nationalgeographic.com/news/2014/02/140213-amazon-river-length-source-maps-science/ |title=Where Does the Amazon River Begin? |date=15 February 2014 |website=National Geographic News |access-date=25 December 2018 |archive-url=https://web.archive.org/web/20190327091707/https://news.nationalgeographic.com/news/2014/02/140213-amazon-river-length-source-maps-science/ |archive-date=27 March 2019 }}</ref>}}
(''Amazon–Marañón'' {{cvt|5,700|km|mi|abbr=on}}<ref name="The Amazon River"/>
| width_min = {{cvt|700|m}} (Upper Amazon); {{cvt|1.5|km|mi}} ([[Itacoatiara, Amazonas|Itacoatiara]], Lower Amazon)<ref name="Issues of local and global use of water from the Amazon"/>
| width_avg = {{cvt|3|km|mi}} (Middle Amazon); {{cvt|5|km|mi}} (Lower Amazon)<ref name="Issues of local and global use of water from the Amazon"/><ref name="Seasonal assessment of groundwater quality in the cities of Itacoatiara and Manacapuru (Amazon, Brazil)">{{cite web |url=https://www.researchgate.net/publication/333157040 |title=Seasonal assessment of groundwater quality in the cities of Itacoatiara and Manacapuru (Amazon, Brazil) |last1=Anderson da Silva |first1=Layes |last2=Marcondes Silva |first2=E. Silva |last3=Genilson Pereira |first3=Santana}}</ref>
| width_max = {{cvt|10-14|km|mi}} (Lower Amazon);<ref name="Issues of local and global use of water from the Amazon"/><ref name="Amazon River-Hydrology">{{cite web |url=https://www.britannica.com/place/Amazon-River/Hydrology |title=Amazon River-Hidrology |access-date=2 November 2022 |archive-date=14 October 2023 |archive-url=https://web.archive.org/web/20231014092545/https://www.britannica.com/place/Amazon-River/Hydrology |url-status=live }}</ref> {{cvt|340|km|mi}} (estuary)<ref name="Aguas Amazonicas">{{cite web |url=http://www.amazonwaters.org/ |title=Aguas Amazonicas |access-date=1 November 2022 |archive-date=3 July 2023 |archive-url=https://web.archive.org/web/20230703195120/https://amazonwaters.org/ |url-status=live }}</ref>
| depth_min = 
| depth_avg = {{cvt|15-45|m}} (Middle Amazon); {{cvt|20-50|m}} (Lower Amazon)<ref name="Issues of local and global use of water from the Amazon"/>
| depth_max = {{cvt|150|m}} ([[Itacoatiara, Amazonas|Itacoatiara]]); {{cvt|130|m}} ([[Óbidos, Brazil|Óbidos]])<ref name="Issues of local and global use of water from the Amazon">{{cite web |url=https://unesdoc.unesco.org/ark:/48223/pf0000136195 |title=Issues of local and global use of water from the Amazon |access-date=1 November 2022 |archive-date=14 October 2023 |archive-url=https://web.archive.org/web/20231014093334/https://unesdoc.unesco.org/ark:/48223/pf0000136195 |url-status=live }}</ref><ref name="Seasonal assessment of groundwater quality in the cities of Itacoatiara and Manacapuru (Amazon, Brazil)"/>
| discharge2_location =Near mouth 
| discharge2_min = 
| discharge2_avg =
(''without Tocantins'')
{{cvt|206,000-215,000|m3/s|sp=us}}
<ref name="erudit">Jacques Callède et.&nbsp;al.: ''[http://id.erudit.org/iderudit/044688ar Les apports en eau de l'Amazone à l'Océan Atlantique] {{Webarchive|url=https://web.archive.org/web/20231102051620/https://www.erudit.org/fr/revues/rseau/2010-v23-n3-rseau3946/044688ar/ |date=2 November 2023 }}.'' In: ''Revue des sciences de l'eau / Journal of Water Science.'' Bd. 23, Nr. 3, Montreal 2010, S. 247–273 (retrieved 19 August 2013)</ref><ref name="ref01">{{cite web |url=https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers16-04/010014008.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers16-04/010014008.pdf |archive-date=2022-10-09 |url-status=live |title=EAUX, GLACIERS & CHANGEMENTS CLIMATIQUES DANS LES ANDES TROPICALES - Institut Français d'Études Andines - Institut Français de Recherche Scientifique pour le Développement en Cooperation |last1=Pierre |first1=Ribstein |last2=Bernard |first2=Francou |last3=Anne |first3=Coudrain Ribstein |last4=Philippe |first4=Mourguiart |year=1995}}</ref><ref name="hy1">{{cite web |title=Hydrological Control on the Temporal Variability of Trace Element Concentration in the Amazon River and its Main Tributaries |last=Seyler |first=Patrick |author2=Laurence Maurice-Bourgoin |author3=Jean Loup Guyot |publisher=Geological Survey of Brazil (CPRM) |url=http://www.cprm.gov.br/pgagem/Manuscripts/seylerp.htm |access-date=24 July 2010 |url-status=live |archive-url=https://web.archive.org/web/20110721224824/http://www.cprm.gov.br/pgagem/Manuscripts/seylerp.htm |archive-date=21 July 2011 |df=dmy-all}}</ref>
| discharge2_max = 
| source1 = [[Apurímac River]], [[Nevado Mismi|Mismi Peak]]
| source1_location = [[Arequipa Region]], [[Peru]]
| source1_coordinates = {{coord|15|31|04|S|71|41|37|W|display=inline,title}}
| source1_elevation = {{cvt|5,220|m|sp=us}}
| mouth = [[Atlantic Ocean]]
| mouth_location = [[Brazil]]
| mouth_coordinates = {{coord|0|42|28|N|50|5|22|W|type:_river}}<ref>{{GEOnet2|32FA88417DB73774E0440003BA962ED3|Amazon River}}</ref>
| progression = 
| river_system = '''Amazon River'''
| basin_size =
(''with Tocantins'')
{{cvt|6,743,000|sqkm|sp=us}}<ref name="osinfor22e">{{cite web |url=https://www.osinfor.gob.pe/portal/data/documentos/osinfor_minambiente/29102015/22e.pdf |title=CORPOAMAZONIA - TRÁMITES PARA APROVECHAMIENTO FORESTAL |access-date=8 October 2021 |archive-date=6 January 2023 |archive-url=https://web.archive.org/web/20230106052443/https://www.osinfor.gob.pe/portal/data/documentos/osinfor_minambiente/29102015/22e.pdf |url-status=live }}</ref>–{{cvt|7,000,000|sqkm|sp=us}}<ref name="britannica-amazon"/><ref name="HYD1">{{cite book|url=https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2022-02/010010558.pdf|title=HYDROLOGIE DU BASSIN AMAZONIEN|year=1997|isbn=2-7011-1532-9|last1=Théry |first1=Hervé |last2=Maurence |first2=Pascale }}</ref>
(''5,956,000–6,112,000 km<sup>2</sup> without Tocantins''<ref name="erudit"/><ref name="HYD1"/>)
| tributaries_left = [[Marañón River|Marañón]], [[Nanay River|Nanay]], [[Napo River|Napo]], Ampiyaçu, [[Putumayo River|Putumayo]], [[Japurá River|Japurá]], [[Badajós River|Badajós]], [[Manacapuru River|Manacapuru]], [[Rio Negro (Amazon)|Rio Negro]], [[Urubu River (Amazonas)|Urubu]], [[Uatumã River|Uatumã]], [[Nhamundá River|Nhamundá]], [[Trombetas River|Trombetas]], [[Maicuru River|Maicurú]], [[Curuá River (Amazon River tributary)|Curuá]], [[Paru River|Paru]], [[Jari River|Jari]]
| tributaries_right = [[Ucayali River|Ucayali]], [[Jandiatuba River|Jandiatuba]], [[Javary River|Javary]], [[Jutai River|Jutai]], [[Juruá]], [[Tefé River|Tefé]], [[Coari River|Coari]], [[Purús River|Purús]], [[Madeira River|Madeira]], [[Canumã River|Paraná do Ramos]], [[Tapajós River|Tapajós]], [[Curuá Una River|Curuá-Una]], [[Xingu River|Xingu]], [[Pará River|Pará]], [[Tocantins River|Tocantins]], [[Acará River|Acará]], [[Guamá River|Guamá]]
| custom_label = 
| custom_data = 
| extra =  
| discharge1_location = [[Amazon Delta]]
| discharge1_min = {{cvt|180,000|m3/s|cuft/s|abbr=on}}
| discharge1_avg =
(''with Tocantins'')
(Period: 2003–2015){{cvt|230,000|m3/s|cuft/s}}
<ref name="osinfor22e"/><ref name="ref01"/><ref name="hy1"/>{{refn|name=discharge1|group=n|Multiannual average discharge {{cvt|220,800-223,700|m3/s|cuft/s|abbr=on}}<ref name="HYD1"/><ref>{{cite book|last1=Charles J.|first1=Vörösmarty|last2=Berrien|first2=Moore|last3=Annette L.|first3=Grace|last4=M. Patricia|first4=Gildea|url=https://gmao.gsfc.nasa.gov/gmaoftp/sarith/ROUTING_MODEL/docs/Vorosmarty_1989.pdf|title=CONTINENTAL SCALE MODELS OF WATER BALANCE AND FLUVIAL TRANSPORT: AN APPLICATIONS TO SOUTH AMERICA|volume=3|pages=241–265|year=1989}}</ref>}}
| discharge1_max={{cvt|340,000|m3/s|cuft/s|abbr=on}}
| discharge3_location = [[Santarém, Pará|Santarém]]
| discharge3_min = (Period: 1998–2023){{cvt|82,160|m3/s|cuft/s|abbr=on}}<ref name="River and Reservoir Watch Version 4.5-148">{{cite web|url=https://floodobservatory.colorado.edu/SiteDisplays/148data.htm|title=River and Reservoir Watch Version 4.5-148}}</ref>
| discharge3_avg = (Period: 1971–2000){{cvt|191,624|m3/s|cuft/s|abbr=on}}<ref name="Lower Amazon">{{cite web|url=https://www.riversnetwork.org/V1/index.php/component/content/?view=article&id=43&catid=191&Itemid=179|title=Lower Amazon}}</ref>
| discharge3_max = (Period: 1998–2023){{cvt|298,400|m3/s|cuft/s|abbr=on}}<ref name="River and Reservoir Watch Version 4.5-148"/>
| discharge4_location = [[Óbidos, Brazil|Óbidos]]
| discharge4_avg = (Period: 1903–2023){{cvt|165,829.6|m3/s|cuft/s|abbr=on}}<ref name="ANA">{{cite web|url=https://www.gov.br/ana/pt-br|title=ANA}}</ref>{{refn|name=discharge4|group=n|(Period: 1971–2000){{cvt|173,272.6|m3/s|cuft/s}}<ref name="Lower Amazon"/>
(Period: 1928–1996){{cvt|176,177|m3/s|cuft/s}}<ref name="GRDC">GRDC: [http://www.compositerunoff.sr.unh.edu/html/Polygons/P3629000.html Daten des Pegels ''Óbidos''] {{Webarchive|url=https://web.archive.org/web/20220809114257/https://www.compositerunoff.sr.unh.edu/html/Polygons/P3629000.html |date=9 August 2022 }}</ref>
(Period: 01/01/1997–31/12/2015){{cvt|178,193.9|m3/s|cuft/s}}<ref name="Assess1">{{cite web |url=https://hess.copernicus.org/articles/23/3057/2019/hess-23-3057-2019-supplement.pdf |title=Assessing the performance of global hydrological models for capturing peak river flows in the Amazon basin |last=Jamie |first=Towner |year=2019 |access-date=28 March 2022 |archive-date=14 October 2023 |archive-url=https://web.archive.org/web/20231014093200/https://hess.copernicus.org/articles/23/3057/2019/hess-23-3057-2019-supplement.pdf |url-status=live }}</ref>}}
| discharge4_min =(Period: 1903–2023){{cvt|95,000|m3/s|cuft/s|abbr=on}}<ref name="ANA"/>
| discharge4_max =(Period: 1903–2023){{cvt|260,000|m3/s|cuft/s|abbr=on}}<ref name="ANA"/>
| discharge5_location = [[Manacapuru]]
| discharge5_avg = (Period: 1997–2015)
{{cvt|105,720|m3/s|cuft/s}}<ref name="Assess1"/>
}}
[[File:Amazonas und Reliefkarte.png|thumb|upright=1.3|Topography of the Amazon River Basin]]

The '''Amazon River''' ({{IPAc-en|uk|ˈ|æ|m|ə|z|ən}}, {{IPAc-en|us|ˈ|æ|m|ə|z|ɒ|n}}; {{langx|es|Río Amazonas}}, {{langx|pt|Rio Amazonas}}) in [[South America]] is the [[List of rivers by discharge|largest river by discharge]] volume of water in the world, and the [[List of river systems by length|longest or second-longest river system in the world]], a title which is disputed with the [[Nile]].<ref name="britannica-amazon"/><ref>{{cite journal |last1=Uereyen |first1=Soner |last2=Kuenzer |first2=Claudia |title=A Review of Earth Observation-Based Analyses for Major River Basins |journal=Remote Sensing |date=9 December 2019 |volume=11 |issue=24 |page=2951 |doi=10.3390/rs11242951 |bibcode=2019RemS...11.2951U |doi-access=free| issn = 2072-4292}} As well as being the largest river [by volume], the Amazon River is home to many species of fish.</ref>{{refn|The [[Nile]] is usually said to be the longest river in the world, with a length of about {{cvt|6650|km|mi}},<ref name=britannica-nile/> and the Amazon the second longest river in the world, with a length of at least {{cvt|6400|km|mi}}.<ref name=britannica-amazon/> In 2007 and 2008, some scientists claimed that the Amazon has a length of {{cvt|6992|km|mi}} and was longer than the Nile, whose length was calculated as {{cvt|6853|km|mi}}.<ref name=bbc-amazon/><ref name=Roach>{{cite magazine|last1=Roach|first1=John|date=2007-06-18|location=[[Washington D.C.]]|title=Amazon Longer Than Nile River, Scientists Say|url=https://www.nationalgeographic.com/science/article/amazon-longer-than-nile-river|url-access= |trans-title= |format= |department= |magazine=[[National Geographic]]|language=en-US|publisher=[[National Geographic Partners]]|issn=0027-9358|oclc=643483454|url-status=live|archive-url=https://web.archive.org/web/20241215180734/https://www.nationalgeographic.com/science/article/amazon-longer-than-nile-river|archive-date=2024-12-15|access-date=2017-08-15}}</ref> A [[Peer review|peer-reviewed]] article, published in 2009, states a length of {{cvt|7088|km|mi}} for the Nile and {{cvt|6575|km|mi}} for the Amazon, measured by using a combination of satellite image analysis and field investigations to the source regions.<ref name="liu-etal-river-length">{{Cite journal |last1=Liu |first1=Shaochuang |last2=Lu |first2=P |last3=Liu |first3=D |last4=Jin |first4=P |last5=Wang |first5=W |date=1 March 2009 |title=Pinpointing the sources and measuring the lengths of the principal rivers of the world |url=https://www.researchgate.net/publication/220473241 |journal=Int. J. Digit. Earth |volume=2 |issue=1 |pages=80–87 |doi=10.1080/17538940902746082 |bibcode=2009IJDE....2...80L |s2cid=27548511 |access-date=29 December 2018 |archive-url=https://web.archive.org/web/20181223211543/https://www.researchgate.net/publication/220473241_Pinpointing_the_sources_and_measuring_the_lengths_of_the_principal_rivers_of_the_world |archive-date=23 December 2018 |url-status=live}}</ref>
According to the [[Encyclopædia Britannica]], as of 2020, the length of the Amazon remains open to interpretation and continued debate.<ref name=britannica-amazon/><ref name=britannica-amazon-length>{{Cite web |url=https://www.britannica.com/story/how-long-is-the-amazon-river |title=How Long Is the Amazon River? |website=Encyclopedia Britannica |language=en |access-date=24 December 2018 |archive-url=https://web.archive.org/web/20181224171204/https://www.britannica.com/story/how-long-is-the-amazon-river |archive-date=24 December 2018 |url-status=live}}</ref>|name=longest|group=n}}

The headwaters of the [[Apurímac River]] on [[Nevado Mismi]] had been considered, for nearly a century, the [[Amazon basin]]'s most distant source until a 2014 study found it to be the headwaters of the [[Mantaro River]] on the Cordillera Rumi Cruz in [[Peru]].<ref name="ContosTripcevich">{{cite journal |author1=James Contos |author2=Nicholas Tripcevich |title=Correct placement of the most distant source of the Amazon River in the Mantaro River drainage |journal=Area |date=March 2014 |volume=46 |issue=1 |pages=27–39 |doi=10.1111/area.12069 |bibcode=2014Area...46...27C |url=https://escholarship.org/content/qt6js988dk/qt6js988dk.pdf?t=nmjqr2 |access-date=30 August 2019 |archive-date=26 January 2021 |archive-url=https://web.archive.org/web/20210126182635/https://escholarship.org/content/qt6js988dk/qt6js988dk.pdf?t=nmjqr2 |url-status=live }}</ref> The Mantaro and [[Apurímac River|Apurímac]] rivers join, and with other tributaries form the [[Ucayali River]], which in turn meets the [[Marañón River]] upstream of [[Iquitos]], Peru, forming what countries other than [[Brazil]] consider to be the [[main stem]] of the Amazon. Brazilians call this section the [[Solimões River]] above its confluence with the [[Rio Negro (Amazon)|Rio Negro]]<ref name=Penn>{{cite book |last=Penn |first=James R. |title=Rivers of the World |year=2001 |publisher=ABC-CLIO |isbn=978-1-57607-042-0 |url=https://archive.org/details/riversofworldsoc00penn |url-access=registration |page=[https://archive.org/details/riversofworldsoc00penn/page/8 8] |df=dmy-all}}</ref> forming what Brazilians call the Amazon at the [[Meeting of Waters]] ({{langx|pt|Encontro das Águas}}) at [[Manaus]], the largest city on the river.

The Amazon River has an average discharge of about {{cvt|215,000|–|230,000|m3/s|sp=us}}—approximately {{cvt|6,591|–|7,570|km3||sp=us}} per year, greater than the next seven largest independent rivers combined. Two of the top ten rivers by discharge are [[tributaries]] of the Amazon river. The Amazon represents 20% of the global riverine discharge into oceans.<ref name="auto">{{cite journal |last1=Moura |first1=Rodrigo L. |last2=Amado-Filho |first2=Gilberto M. |last3=Moraes |first3=Fernando C. |last4=Brasileiro |first4=Poliana S. |last5=Salomon |first5=Paulo S. |last6=Mahiques |first6=Michel M. |last7=Bastos |first7=Alex C. |last8=Almeida |first8=Marcelo G. |last9=Silva |first9=Jomar M.|last10=Araujo|first10=Beatriz F. |last11=Brito |first11=Frederico P. |last12=Rangel |first12=Thiago P. |last13=Oliveira |first13=Braulio C.V. |last14=Bahia |first14=Ricardo G. |last15=Paranhos |first15=Rodolfo P. |last16=Dias |first16=Rodolfo J. S. |last17=Siegle |first17=Eduardo |last18=Figueiredo |first18=Alberto G. |last19=Pereira |first19=Renato C.|last20=Leal|first20=Camellia V. |last21=Hajdu |first21=Eduardo |last22=Asp |first22=Nils E. |last23=Gregoracci |first23=Gustavo B. |last24=Neumann-Leitão |first24=Sigrid |last25=Yager |first25=Patricia L. |last26=Francini-Filho |first26=Ronaldo B. |last27=Fróes |first27=Adriana |last28=Campeão |first28=Mariana |last29=Silva |first29=Bruno S.|last30=Moreira|first30=Ana P.B. |last31=Oliveira |first31=Louisi |last32=Soares |first32=Ana C. |last33=Araujo |first33=Lais |last34=Oliveira |first34=Nara L. |last35=Teixeira |first35=João B. |last36=Valle |first36=Rogerio A.B. |last37=Thompson |first37=Cristiane C. |last38=Rezende |first38=Carlos E. |last39=Thompson |first39=Fabiano L. |title=An extensive reef system at the Amazon River mouth |journal=[[Science Advances]] |date=1 April 2016 |volume=2 |issue=4 |pages=e1501252 |doi=10.1126/sciadv.1501252 |language=en |pmc=4846441 |pmid=27152336 |bibcode=2016SciA....2E1252M}}</ref> The Amazon basin is the largest [[drainage basin]] in the world, with an area of approximately {{cvt|7,000,000|km2|sp=us}}.<ref name=britannica-amazon/> The portion of the river's drainage basin in Brazil alone is larger than any other river's basin. The Amazon enters Brazil with only one-fifth of the flow it finally discharges into the [[Atlantic Ocean]], yet already has a greater flow at this point than the discharge of any other river in the world.<ref name="sterling">Tom Sterling: ''Der Amazonas''. Time-Life Bücher 1979, 7th German Printing, p. 19.</ref><ref name=smith>{{cite book |last=Smith |first=Nigel J.H. |title=Amazon Sweet Sea: Land, Life, and Water at the River's Mouth |year=2003 |publisher=University of Texas Press |isbn=978-0-292-77770-5 |url=https://books.google.com/books?id=SywgnV96puYC&pg=PA1 |pages=1–2 |url-status=live |archive-url=https://web.archive.org/web/20150915123518/https://books.google.com/books?id=SywgnV96puYC&pg=PA1 |archive-date=15 September 2015 |df=dmy-all}}</ref> It has a recognized length of 6,400&nbsp;km (3977 miles) but according to some reports its length varies from 6,992 to 7,062&nbsp;km (4,345–4,388 miles).

==Etymology==
The Amazon was initially known by [[Ethnic groups in Europe|Europeans]] as the [[Marañón River|Marañón]], and the [[Peruvians|Peruvian]] part of the river is still known by that name, as well as the Brazilian state of [[Maranhão]], which contains part of the Amazon. It later became known as Rio Amazonas in [[Spanish language|Spanish]] and [[Portuguese language|Portuguese.]]

The name Rio Amazonas was reportedly given after native warriors attacked a 16th-century expedition by [[Francisco de Orellana]]. The warriors were led by women, reminding de Orellana of the [[Amazons|Amazon warriors]], a tribe of women warriors related to [[Iranian peoples|Iranian]] [[Scythians]] and [[Sarmatians]]<ref name="theoi.com">{{Cite web |url=http://www.theoi.com/Olympios/AresFamily.html |title=Apollonius Rhodius, Argonautica, Book 2 |access-date=15 October 2018 |archive-url=https://web.archive.org/web/20170830025406/http://www.theoi.com/Olympios/AresFamily.html |archive-date=30 August 2017 |url-status=live}}</ref><ref name="ARGONAUTICA BOOK 2">{{Cite web |url=http://sacred-texts.com/cla/argo/argo23.htm |title=Argonautica Book 2 |access-date=15 October 2018 |archive-url=https://web.archive.org/web/20181005183749/http://sacred-texts.com/cla/argo/argo23.htm |archive-date=5 October 2018 |url-status=live}}</ref> mentioned in [[Greek mythology]].
The word Amazon itself may be derived from the [[Iranian peoples|Iranian]] compound * ha-maz-an- "(one) fighting together"<ref>"Amazon| Origin And Meaning Of Amazon By Online Etymology Dictionary". 2018. Etymonline.Com. Accessed 15 October 2018. [https://www.etymonline.com/word/Amazon#etymonline_v_10951] {{Webarchive|url=https://web.archive.org/web/20181015192445/https://www.etymonline.com/word/Amazon#etymonline_v_10951|date=15 October 2018}}.</ref> or [[ethnonym]] ''* ha-mazan-'' "warriors", a word attested indirectly through a derivation, a denominal verb in [[Hesychius of Alexandria]]'s gloss {{lang|grc|"ἁμαζακάραν· πολεμεῖν. Πέρσαι"}} ("''{{transliteration|grc|hamazakaran}}'': 'to make war' in Persian"), where it appears together with the [[Indo-Iranian languages|Indo-Iranian]] root ''* kar-'' "make" (from which [[Sanskrit]] ''[[karma]]'' is also derived).<ref>Lagercrantz, ''Xenia Lidéniana'' (1912), 270ff., cited after [[Hjalmar Frisk]], ''Greek Etymological Dictionary'' (1960–1970)</ref>

Other scholars{{who|date=September 2022}} claim that the name is derived from the [[Tupi language|Tupi]] word ''amassona'', meaning "boat destroyer".<ref>"Amazon River", Encarta Encyclopedia, Microsoft Student 2009 DVD.</ref>{{citation needed|date=February 2025}}

== History ==
{{Main|Timeline of Amazon history}}

=== Geological history ===
Recent [[Geology|geological]] studies suggest that for millions of years, the Amazon River flowed in the opposite direction – from east to west. Eventually the [[Andes Mountains]] formed, blocking its flow to the [[Pacific Ocean]] and causing it to switch directions to its current mouth in the [[Atlantic Ocean]].<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/science/nature/6080232.stm |title=Amazon river 'switched direction' |date=24 October 2006 |access-date=12 April 2021 |archive-date=14 October 2023 |archive-url=https://web.archive.org/web/20231014093041/http://news.bbc.co.uk/2/hi/science/nature/6080232.stm |url-status=live }}</ref>

=== Pre-Columbian era ===<!--NOTE; no typo; pre-Columbian refers to "before Columbus", not "before Columbia"-->
[[File: Brazil, the Amazons and the coast (1879) (14780994814).jpg|thumb|Old drawing (from 1879) of [[Arapaima]] fishing at the Amazon river. The arapaima has been on Earth for at least 23 million years.<ref>{{cite journal |author1=Lundberg, J.G. |author2=B. Chernoff |name-list-style=amp |year=1992 |title=A Miocene fossil of the Amazonian fish Arapaima (Teleostei, Arapaimidae) from the Magdalena River region of Colombia--Biogeographic and evolutionary implications |journal=Biotropica |volume=24 |pages=2–14 |issue=1 |doi=10.2307/2388468 |jstor=2388468|bibcode=1992Biotr..24....2L }}</ref>]]

During what many [[archaeologist]]s called the ''[[formative stage]]'', Amazonian societies were deeply involved in the emergence of [[South America|South America's]] highland [[agriculture|agrarian]] systems. The [[Muisca economy#Trade|trade]] with [[Andean civilizations]] in the terrains of the [[headwaters]] in the [[Andes]] formed an essential contribution to the social and religious development of higher-altitude civilizations like the [[Muisca Confederation|Muisca]] and [[Inca Empire|Incas]]. Early human settlements were typically based on low-lying hills or mounds.

[[Midden|Shell mounds]] were the earliest evidence of habitation; they represent piles of human refuse (waste) and are mainly dated between 7500&nbsp;BC and 4000&nbsp;BC. They are associated with [[ceramic age cultures]]; no preceramic shell mounds have been documented so far by [[Archaeology|archaeologists]].<ref>{{Cite book |last1=Silberman |first1=Neil Asher |url=https://books.google.com/books?id=xeJMAgAAQBAJ&q=no+preceramic+shell+mounds+have+been+documented+so+far+by+archaeologists&pg=RA1-PA429 |title=The Oxford Companion to Archaeology |last2=Bauer |first2=Alexander A. |date=November 2012 |publisher=OUP USA |isbn=978-0-19-973578-5 |page=429 |language=en |access-date=5 August 2021 |archive-date=2 November 2023 |archive-url=https://web.archive.org/web/20231102051716/https://books.google.com/books?id=xeJMAgAAQBAJ&q=no+preceramic+shell+mounds+have+been+documented+so+far+by+archaeologists&pg=RA1-PA429#v=snippet&q=no%20preceramic%20shell%20mounds%20have%20been%20documented%20so%20far%20by%20archaeologists&f=false |url-status=live }}</ref> Artificial earth platforms for entire villages are the second type of mounds. They are best represented by the [[Marajoara culture]]. [[Figurative mound]]s are the most recent types of occupation.

There is ample evidence that the areas surrounding the Amazon River were home to complex and large-scale indigenous societies, mainly [[chiefdom]]s who developed towns and cities.<ref>{{Cite journal |last=Roosevelt |first=Anna Curtenius |date=1993 |title=The Rise and Fall of the Amazon Chiefdoms |journal=L'Homme |volume=33 |issue=126/128 |pages=255–283 |doi=10.3406/hom.1993.369640 |jstor=40589896 |issn=0439-4216}}</ref> [[Archaeology|Archaeologists]] estimate that by the time the [[Spanish conquistador]] De Orellana traveled across the Amazon in 1541, more than 3 million indigenous people lived around the Amazon.<ref name=Wohl>{{cite book|last1=Wohl|first1=Ellen E|author-link1=Ellen E. Wohl|year=2011|chapter=2. The Amazon: Rivers of Blushing Dolphins|location=[[Chicago]]|title=A world of Rivers: Environmental Change on Ten of the World's great rivers|url=https://press.uchicago.edu/ucp/books/book/chicago/W/bo9396888.html|url-access=subscription|language=en-us|publisher=[[University of Chicago Press]]|isbn=9780226904801|oclc=690177774|url-status=live|archive-url=https://web.archive.org/web/20240411180730/https://press.uchicago.edu/ucp/books/book/chicago/W/bo9396888.html|archive-date=2024-04-11|access-date=2020-05-23}}</ref>{{rp|24&ndash;25}} These [[Pre-Columbian era|pre-Columbian]] settlements created highly developed civilizations. For instance, pre-Columbian [[indigenous peoples of Brazil|indigenous people]] on the island of [[Marajó]] may have developed social stratification and supported a population of 100,000 people. To achieve this level of development, the indigenous inhabitants of the [[Amazon rainforest]] altered the forest's [[ecology]] by [[selective cultivation]] and the use of fire. Scientists argue that by burning areas of the forest repeatedly, the indigenous people caused the soil to become richer in nutrients. This created dark soil areas known as ''[[terra preta]] de índio'' ("Indian dark earth").<ref name=Wohl/>{{rp|25}} Because of the terra preta, indigenous communities were able to make land fertile and thus sustainable for the large-scale agriculture needed to support their large populations and complex social structures. Further research has hypothesized that this practice began around 11,000 years ago. Some say that its effects on [[forest ecology]] and regional climate explain the otherwise inexplicable band of lower rainfall through the [[Amazon basin]].<ref name=Wohl/>{{rp|25}}

Many indigenous tribes engaged in constant [[Tribal warfare|warfare]]. According to [[James S. Olson]], "The [[Munduruku]] expansion (in the 18th century) dislocated and displaced the [[Kawahíb people|Kawahíb]], breaking the tribe down into much smaller groups&nbsp;... [Munduruku] first came to the attention of [[Ethnic groups in Europe|Europeans]] in 1770 when they began a series of widespread attacks on Brazilian settlements along the Amazon River."<ref>{{cite book |first=James Stuart |last=Olson |title=The Indians of Central and South America: an ethnohistorical dictionary |url=https://books.google.com/books?id=175c4xOpLtYC&pg=PA57 |publisher=Greenwood Publishing Group |year=1991 |pages=57–248 |isbn=978-0-313-26387-3 |url-status=live |archive-url=https://web.archive.org/web/20150912153816/https://books.google.com/books?id=175c4xOpLtYC&pg=PA57&dq |archive-date=12 September 2015}}</ref>

=== Arrival of Europeans ===
[[File: Amazon CIAT (2).jpg|thumb|Amazon tributaries near Manaus]]

In March 1500, [[Spanish Empire|Spanish]] [[conquistador]] [[Vicente Yáñez Pinzón]] was the first documented [[Ethnic groups in Europe|European]] to sail up the Amazon River.<ref name=Morison1974>{{cite book |last=Morison |first=Samuel |title=The European Discovery of America: The Southern Voyages, 1492–1616 |url=https://archive.org/details/europeandiscover00mori |url-access=registration |publisher=Oxford University Press |year=1974 |location=New York}}</ref> [[Pinzón Island|Pinzón]] called the stream ''Río Santa María del Mar Dulce'', later shortened to ''Mar Dulce'', literally, ''sweet sea'', because of its freshwater pushing out into the ocean. Another [[Spanish language|Spanish]] explorer, [[Francisco de Orellana]], was the first [[European Union|European]] to travel from the origins of the upstream river basins, situated in the [[Andes]], to the mouth of the river. In this journey, Orellana baptized some of the affluents of the Amazonas like [[Rio Negro (Amazon)|Rio Negro]], [[Napo River|Napo]] and [[Juruá River|Jurua]].
The name Amazonas is thought to be taken from the native warriors that attacked this expedition, mostly women, that reminded De Orellana of the mythical female [[Amazons|Amazon]] warriors from the ancient [[Ancient Greece|Hellenic culture]] in Greece (see also [[#Etymology|Origin of the name]]).

=== Exploration ===
[[File: The Marañon or Amazon River with the Mission of the Society of Jesus WDL1137.png|thumb|[[Samuel Fritz]]'s 1707 map showing the Amazon and the Orinoco]]

[[Gonzalo Pizarro]] set off in 1541 to explore east of [[Quito]] into the South American interior in search of ''[[El Dorado]]'', the "city of gold" and [[La Canela]], the "valley of [[cinnamon]]".<ref>[https://www.britannica.com/EBchecked/topic/431769/Francisco-de-Orellana Francisco de Orellana Francisco de Orellana (Spanish explorer and soldier)] {{webarchive |url=https://web.archive.org/web/20090503155124/https://www.britannica.com/EBchecked/topic/431769/Francisco-de-Orellana |date=3 May 2009 }}. Encyclopædia Britannica.</ref> He was accompanied by his second-in-command [[Francisco de Orellana]]. After {{cvt|170.|km|sp=us}}, the [[Coca River]] joined the [[Napo River]] (at a point now known as [[Puerto Francisco de Orellana]]); the party stopped for a few weeks to build a boat just upriver from this confluence. They continued downriver through an uninhabited area, where they could not find food. Orellana offered and was ordered to follow the Napo River, then known as ''Río de la Canela'' ("Cinnamon River"), and return with food for the party. Based on intelligence received from a captive native chief named Delicola, they expected to find food within a few days downriver by ascending another river to the north.

De Orellana took about 57 men, the boat, and some canoes and left Pizarro's troops on 26 December 1541. However, De Orellana missed the confluence (probably with the [[Aguarico River|Aguarico]]) where he was searching supplies for his men. By the time he and his men reached another village, many of them were sick from hunger and eating "noxious plants", and near death. Seven men died in that village. His men threatened to mutiny if the expedition turned back to attempt to rejoin Pizarro, the party being over 100 leagues downstream at this point. He accepted to change the purpose of the expedition to discover new lands in the name of the king of Spain, and the men built a larger boat in which to navigate downstream. After a journey of {{cvt|600|km|sp=us}} down the Napo River, they reached a further major confluence, at a point near modern [[Iquitos]], and then followed the upper Amazon, now known as the Solimões, for a further {{cvt|1200.|km|sp=us}} to its confluence with the Rio Negro (near modern [[Manaus]]), which they reached on 3 June 1542.

Regarding the initial mission of finding cinnamon, Pizarro reported to the king that they had found cinnamon trees, but that they could not be profitably harvested. True cinnamon (''Cinnamomum Verum'') is not native to South America. Other related cinnamon-containing plants (of the family ''Lauraceae'') are fairly common in that part of the Amazon and Pizarro probably saw some of these. The expedition reached the mouth of the Amazon on 24 August 1542, demonstrating the practical navigability of the Great River.

[[File: Naturalist on the River Amazons figure 38.png|thumb|Masked-dance, and wedding-feast of [[Ticuna|Ticuna Indians]], engravings for Bates's 1863 ''[[The Naturalist on the River Amazons]]'']]

In 1560, another Spanish [[conquistador]], [[Lope de Aguirre]], may have made the second descent of the Amazon. Historians are uncertain whether the river he descended was the Amazon or the [[Orinoco River]], which runs more or less parallel to the Amazon further north.

Portuguese explorer [[Pedro Teixeira]] was the first European to travel up the entire river. He arrived in Quito in 1637, and returned via the same route.<ref>{{cite web |url=http://www.projectamazonas.org/brief-history-amazon-exploration |title=A Brief History of Amazon Exploration |last=Graham |first=Devon |publisher=Project Amazonas |access-date=18 July 2014 |url-status=live |archive-url=https://web.archive.org/web/20140725230550/http://www.projectamazonas.org/brief-history-amazon-exploration |archive-date=25 July 2014}}</ref>

From 1648 to 1652, Portuguese Brazilian ''[[bandeirante]]'' [[António Raposo Tavares]] led an expedition from [[São Paulo]] overland to the mouth of the Amazon, investigating many of its tributaries, including the Rio Negro, and covering a distance of over {{cvt|10000|km|sp=us}}.

In what is currently in Brazil, Ecuador, Bolivia, Colombia, Peru, and Venezuela, several [[colonization|colonial]] and religious settlements were established along the banks of primary rivers and tributaries for trade, slaving{{citation needed|date=June 2024}} , and [[Evangelism|evangelization]] among the indigenous peoples of the vast rainforest, such as the [[Urarina]]. In the late 1600s, Czech Jesuit Father [[Samuel Fritz]], an apostle of the Omagus established some forty mission villages. Fritz proposed that the [[Marañón River]] must be the source of the Amazon, noting on his 1707 map that the Marañón "has its source on the southern shore of a lake that is called [[Lawriqucha|Lauricocha]], near [[Huánuco]]." Fritz reasoned that the Marañón is the largest river branch one encounters when journeying upstream, and lies farther to the west than any other tributary of the Amazon. For most of the 18th–19th centuries and into the 20th century, the Marañón was generally considered the source of the Amazon.<ref name = "Dias">{{Cite web |url=http://redebrasilis.net/wp-content/uploads/2013/04/Camila-L.-Dias-Jesuit-Maps-and-Political-Discourse-muse.pdf |title=Camila Loureiro Dias, "Maps and Political Discourse: The Amazon River of Father Samuel Fritz," ''The Americas,'' Volume 69, Number 1, July 2012, pp. 95–116. |access-date=15 September 2018 |archive-url=https://web.archive.org/web/20181001180423/http://redebrasilis.net/wp-content/uploads/2013/04/Camila-L.-Dias-Jesuit-Maps-and-Political-Discourse-muse.pdf |archive-date=1 October 2018 |url-status=live}}</ref>

[[File: Naturalist on the River Amazons figure 32.png|thumb|upright|[[Henry Walter Bates]] was most famous for his expedition to the Amazon (1848–1859).]]

=== Scientific exploration ===

Early scientific, zoological, and botanical exploration of the Amazon River and basin took place from the 18th century through the first half of the 19th century.
* [[Charles Marie de La Condamine]] explored the river in 1743.<ref>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/326266/Charles-Marie-de-La-Condamine |title=Charles-Marie de La Condamine (French naturalist and mathematician) |encyclopedia=[[Encyclopædia Britannica Online]] |access-date=18 July 2014 |url-status=live |archive-url=https://web.archive.org/web/20140725132645/https://www.britannica.com/EBchecked/topic/326266/Charles-Marie-de-La-Condamine |archive-date=25 July 2014}}</ref>
* [[Alexander von Humboldt]], 1799–1804
* [[Johann Baptist von Spix]] and [[Carl Friedrich Philipp von Martius]], 1817–1820
* [[Georg von Langsdorff]], 1826–1828 
* [[Henry Walter Bates]] and [[Alfred Russel Wallace]], 1848–1859
* [[Richard Spruce]], 1849–1864

=== Post-colonial exploitation and settlement ===
[[File:Casaamazonica.jpg|thumb|[[Amazonas (Brazilian state)|Amazonas]] state]]
{{multiple image
| align = right
| direction = vertical
| width = 220px
| image1 = Centro de Manaus.jpg
| alt1 = [[Amazon Theatre]] opera house in Manaus built in 1896 during the rubber boom
| caption1 = [[Amazon Theatre]] opera house in Manaus built in 1896 during the rubber boom
| image2 = Catedral Metropolitana de Santarém, Santarém, Pará, 2007.jpg
| alt2 = Metropolitan Cathedral of Santarém, in Santarém, Brazil
| caption2 = Metropolitan Cathedral of Santarém, in [[Santarém, Brazil]]
}}
[[image:Iquitos-2012.jpg|thumb|upright|Iglesia Matriz in [[Iquitos, Peru]]]]
The [[Cabanagem]] revolt (1835–1840) was directed against the white ruling class. It is estimated that from 30% to 40% of the population of [[Grão-Pará Province|Grão-Pará]], estimated at 100,000 people, died.<ref>{{cite web |url=http://noticias.uol.com.br/licaodecasa/materias/fundamental/historia/brasil/ult1689u20.jhtm |title=Cabanagem (1835–1840): Uma das mais sangrentas rebeliões do período regencial |work=[[Universo Online]] Liçao de Casa |author=Renato Cancian |access-date=12 November 2007 |language=pt |archive-url=https://web.archive.org/web/20071102212940/http://noticias.uol.com.br/licaodecasa/materias/fundamental/historia/brasil/ult1689u20.jhtm |archive-date=2 November 2007 |url-status=live}}</ref>

The population of the Brazilian portion of the Amazon basin in 1850 was perhaps 300,000, of whom about 175,000 were Europeans and 25,000 were slaves. The Brazilian Amazon's principal commercial city, Pará (now Belém), had from 10,000 to 12,000 inhabitants, including slaves. The town of Manáos, now Manaus, at the mouth of the Rio Negro, had a population between 1,000 and 1,500. All the remaining villages, as far up as [[Tabatinga]], on the Brazilian frontier of Peru, were relatively small.{{sfn|Church|1911|p=789}}

On 6 September 1850, Emperor [[Pedro II of Brazil]] sanctioned a law authorizing steam navigation on the Amazon and gave the Viscount of Mauá ([[Irineu Evangelista de Sousa]]) the task of putting it into effect. He organised the "Companhia de Navegação e Comércio do Amazonas" in Rio de Janeiro in 1852; in the following year it commenced operations with four small steamers, the ''Monarca'' ('Monarch'), the ''Cametá'', the ''Marajó'' and the ''Rio Negro''.{{sfn|Church|1911|p=789}}<ref>{{cite web |title=Sobre Escravos e Regatões |url=http://www.snh2015.anpuh.org/resources/anais/39/1439329194_ARQUIVO_ANPUHSobreescravoseregatoes1.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.snh2015.anpuh.org/resources/anais/39/1439329194_ARQUIVO_ANPUHSobreescravoseregatoes1.pdf |archive-date=2022-10-09 |url-status=live |access-date=11 December 2015 |language=pt}}</ref>

At first, navigation was principally confined to the main river; and even in 1857 a modification of the government contract only obliged the company to a monthly service between Pará and Manaus, with steamers of 200 tons cargo capacity, a second line to make six round voyages a year between Manaus and Tabatinga, and a third, two trips a month between Pará and Cametá.{{sfn|Church|1911|p=789}} This was the first step in opening up the vast interior.

The success of the venture called attention to the opportunities for economic exploitation of the Amazon, and a second company soon opened commerce on the Madeira, Purús, and Negro; a third established a line between Pará and Manaus, and a fourth found it profitable to navigate some of the smaller streams. In that same period, the Amazonas Company was increasing its fleet. Meanwhile, private individuals were building and running small steam craft of their own on the main river as well as on many of its tributaries.{{sfn|Church|1911|p=789}}

On 31 July 1867, the government of Brazil, constantly pressed by the maritime powers and by the countries encircling the [[upper Amazon]] basin, especially Peru, decreed the opening of the Amazon to all countries, but they limited this to certain defined points: Tabatinga – on the Amazon; Cametá – on the Tocantins; Santarém – on the Tapajós; Borba – on the Madeira, and Manaus – on the Rio Negro. The Brazilian decree took effect on 7 September 1867.{{sfn|Church|1911|p=789}}

Thanks in part to the [[mercantile]] development associated with [[steamboat]] navigation coupled with the internationally driven demand for [[natural rubber]], the Peruvian city of [[Iquitos]] became a thriving, cosmopolitan center of commerce. Foreign companies settled in Iquitos, from where they controlled the extraction of rubber. In 1851 Iquitos had a population of 200, and by 1900 its population reached 20,000. In the 1860s, approximately 3,000 tons of rubber were being exported annually, and by 1911 annual exports had grown to 44,000 tons, representing 9.3% of Peru's exports.<ref>Historia del Peru, Editorial Lexus. p. 93.</ref> During the [[rubber boom]] it is estimated that diseases brought by immigrants, such as [[typhus]] and [[malaria]], killed 40,000 native Amazonians.<ref>La Republica Oligarchic. Editorial Lexus 2000 p. 925.</ref>

The first direct foreign trade with Manaus commenced around 1874. Local trade along the river was carried on by the English successors to the Amazonas Company—the Amazon Steam Navigation Company—as well as numerous small steamboats, belonging to companies and firms engaged in the rubber trade, navigating the Negro, Madeira, Purús, and many other tributaries,{{sfn|Church|1911|p=789}} such as the Marañón, to ports as distant as [[Nauta]], Peru.

By the turn of the 20th century, the exports of the Amazon basin were [[Natural rubber|India-rubber]], [[cacao bean]]s, [[Brazil nut]]s and a few other products of minor importance, such as [[Fur|pelts]] and exotic forest produce ([[resin]]s, barks, woven [[hammock]]s, prized bird [[feather]]s, live animals) and extracted goods, such as [[lumber]] and gold.

=== 20th-century development ===
[[File:Manaus-Amazon-NASA.jpg|thumb|[[Manaus]], the largest city in [[Amazonas (Brazilian state)|Amazonas]], as seen from a [[NASA]] satellite image, surrounded by the dark [[Rio Negro (Amazon)|Rio Negro]] and the muddy Amazon River]]
[[File:Amazonia fotos aérea região de Manaus 2005 AM Brasil - panoramio (8).jpg|thumb|City of Manaus]]
[[File:Sitio de la Victoria regia, Leticia.JPG|thumb|Floating houses in [[Leticia, Amazonas|Leticia]], [[Colombia]]]]

Since colonial times, the Portuguese portion of the Amazon basin has remained a land largely undeveloped by agriculture and occupied by indigenous people who survived the arrival of European diseases.

Four centuries after the European discovery of the Amazon river, the total cultivated area in its basin was probably less than {{cvt|65|km2|sp=us}}, excluding the limited and crudely cultivated areas among the mountains at its extreme headwaters.{{sfn|Church|1911|p=790}} This situation changed dramatically during the 20th century.

Wary of foreign exploitation of the nation's resources, Brazilian governments in the 1940s set out to develop the interior, away from the seaboard where foreigners owned large tracts of land. The original architect of this expansion was president [[Getúlio Vargas]], with the demand for rubber from the Allied forces in World War II providing funding for the drive.

In the 1960s, economic exploitation of the Amazon basin was seen as a way to fuel the "economic miracle" occurring at the time. This resulted in the development of "Operation Amazon", an economic development project that brought large-scale agriculture and ranching to Amazonia. This was done through a combination of credit and fiscal incentives.<ref name=":0">{{Cite book |url=https://books.google.com/books?id=P6k-6rsy7toC&q=operation+amazon+1966&pg=PA32 |title=The Economics of Deforestation in the Amazon: Dispelling the Myths |last=Campari |first=João S. |year=2005 |publisher=Edward Elgar Publishing |isbn=978-1-84542-551-7 |language=en |url-status=live |archive-url=https://web.archive.org/web/20171130235652/https://books.google.com/books?id=P6k-6rsy7toC&pg=PA32&lpg=PA32&dq=operation+amazon+1966&source=bl&ots=d21-mSw_X5&sig=8GsKcFxm_B_EP5NM6QwdcYl_Rk8&hl=en&sa=X&ved=0ahUKEwjd_aLz3-_SAhWKPBQKHYl7BCsQ6AEIXTAP#v=onepage&q=operation%20amazon%201966&f=false |archive-date=30 November 2017}}</ref>

However, in the 1970s the government took a new approach with the National Integration Program (PIN). A large-scale colonization program saw families from northeastern Brazil relocated to the "land without people" in the Amazon Basin. This was done in conjunction with infrastructure projects mainly the [[Trans-Amazonian Highway]] (''Transamazônica'').<ref name=":0" />

The Trans-Amazonian Highway's three pioneering highways were completed within ten years but never fulfilled their promise. Large portions of the Trans-Amazonian and its accessory roads, such as [[BR-317]] (Manaus-[[Porto Velho]]), are derelict and impassable in the rainy season. Small towns and villages are scattered across the forest, and because its vegetation is so dense, some remote areas are still unexplored.

Many settlements grew along the road from Brasília to Belém with the highway and National Integration Program, however, the program failed as the settlers were unequipped to live in the delicate rainforest ecosystem. This, although the government believed it could sustain millions, instead could sustain very few.<ref>{{Cite book |url=https://books.google.com/books?id=XrLl2LxX488C |title=The Fate of the Forest: Developers, Destroyers, and Defenders of the Amazon, Updated Edition |last1=Hecht |first1=Susanna B. |last2=Cockburn |first2=Alexander |year=2010 |publisher=University of Chicago Press |isbn=978-02-263-2272-8 |language=en |access-date=23 May 2020 |archive-date=2 November 2023 |archive-url=https://web.archive.org/web/20231102051617/https://books.google.com/books?id=XrLl2LxX488C |url-status=live }}</ref>

With a population of 1.9 million people in 2014, Manaus is the largest city on the Amazon. Manaus alone makes up approximately 50% of the population of the largest Brazilian state of [[Amazonas (Brazilian state)|Amazonas]]. The racial makeup of the city is 64% [[pardo]] (mulatto and mestizo) and 32% [[White Brazilian|white]].<ref>{{cite book |url=http://www.sidra.ibge.gov.br/bda/tabela/listabl.asp?z=cd&o=7&i=P&c=2094 |title=Síntese de Indicadores Sociais 2000 |publisher=[[Brazilian Institute of Geography and Statistics|IBGE]] |location=Manaus, Brazil |format=PDF |isbn=978-85-240-3919-5 |access-date=31 January 2009 |year=2000 |language=pt |url-status=live |archive-url=https://web.archive.org/web/20110614232328/http://www.sidra.ibge.gov.br/bda/tabela/listabl.asp?z=cd&o=7&i=P&c=2094 |archive-date=14 June 2011}}</ref>

Although the Amazon river remains undammed, around 412 dams are in operation on the Amazon's tributary rivers. Of these 412 dams, 151 are constructed over six of the main tributary rivers that drain into the Amazon.<ref name="theguardian.com">{{cite news |url=https://www.theguardian.com/environment/andes-to-the-amazon/2014/may/06/more-400-dams-amazon-headwaters |last=Hill |first=David |title=More than 400 dams planned for the Amazon and headwaters |newspaper=The Guardian |date=6 May 2014 |location=London |access-date=18 July 2017 |url-status=live |archive-url=https://web.archive.org/web/20170729132329/https://www.theguardian.com/environment/andes-to-the-amazon/2014/may/06/more-400-dams-amazon-headwaters |archive-date=29 July 2017}}</ref> Since only 4% of the Amazon's hydropower potential has been developed in countries like Brazil,<ref name=Wohl/>{{rp|35}} more damming projects are underway and hundreds more are planned.<ref name="auto1">{{cite web |url=http://news.nationalgeographic.com/2015/04/150419-amazon-dams-hydroelectric-deforestation-rivers-brazil-peru |last=Fraser |first=Barbara |title=Amazon Dams Keep the Lights On But Could Hurt Fish, Forests |website=National Geographic |date=19 April 2015 |access-date=25 July 2017 |archive-url=https://web.archive.org/web/20170729182257/http://news.nationalgeographic.com/2015/04/150419-amazon-dams-hydroelectric-deforestation-rivers-brazil-peru/ |archive-date=29 July 2017 |df=dmy-all}}</ref> After witnessing the negative effects of environmental degradation, sedimentation, navigation and flood control caused by the [[Three Gorges Dam]] in the Yangtze River,<ref name=Wohl/>{{rp|279}} scientists are worried that constructing more dams in the Amazon will harm its biodiversity in the same way by "blocking fish-spawning runs, reducing the flows of vital oil nutrients and clearing forests".<ref name="auto1"/> Damming the Amazon River could potentially bring about the "end of free flowing rivers" and contribute to an "[[ecosystem collapse]]" that will cause major social and environmental problems.<ref name="theguardian.com" />

== Course ==
=== Origins ===
{{main|Source of the Amazon River}}
[[File:Amazon origin at Mismi.jpg|thumb|left|upright|The Amazon was thought to originate from the Apacheta cliff in [[Arequipa]] at the [[Nevado Mismi]], marked only by a wooden cross.]]
[[File:The Source of the Amazon River.jpg|thumb|upright=1.3|Nevado Mismi, formerly considered to be the source of the Amazon]]
[[File:Río Marañón 03245.JPG|thumb|[[Marañón River]] in Peru]]

<!--see talk page re most distant source. 15 November 2015-->The most distant source of the Amazon was thought to be in the Apurímac river drainage for nearly a century. Such studies continued to be published even as recently as 1996,<ref name=Palkiewicz>{{cite web |url=http://www.palkiewicz.com/ekspedycje/index.php?p=zrodl_amaz |title=Source of the Amazon River Identificated (Jacek Palkiewicz) |publisher=Palkiewicz.com |date=19 November 1999 |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20070312092613/http://www.palkiewicz.com/ekspedycje/index.php?p=zrodl_amaz |archive-date=12 March 2007}}</ref> 2001,<ref>{{cite magazine |url=http://news.nationalgeographic.com/news/2000/12/1221amazon.html |last=Smith |first=Donald |title=Explorers Pinpoint Source of the Amazon (National Geographic News) |magazine=National Geographic |date=21 December 2000 |access-date=15 July 2017 |archive-url=https://web.archive.org/web/20171101075405/https://news.nationalgeographic.com/news/2000/12/1221amazon.html |archive-date=1 November 2017}}</ref> 2007,<ref name=bbc-amazon>{{cite news |title=Amazon river 'longer than Nile' |work=BBC News |url=http://news.bbc.co.uk/2/hi/6759291.stm |access-date=3 August 2010 |date=16 June 2007 |url-status=live |archive-url=https://web.archive.org/web/20100926054938/http://news.bbc.co.uk/2/hi/6759291.stm |archive-date=26 September 2010 |df=dmy-all}}</ref> and 2008,<ref name=inpe>{{cite web |title=Studies from INPE indicate that the Amazon River is 140&nbsp;km longer than the Nile |publisher=Brazilian National Institute for Space Research |url=http://www.inpe.br/ingles/news/news_dest29.php |access-date=3 August 2010 |archive-url=https://web.archive.org/web/20110411011122/http://www.inpe.br/ingles/news/news_dest29.php |archive-date=11 April 2011}}</ref> where various authors identified the snowcapped {{cvt|5597|m|sp=us}} [[Nevado Mismi]] peak, located roughly {{cvt|160|km|sp=us}} west of [[Lake Titicaca]] and {{cvt|700|km|sp=us}} southeast of [[Lima]], as the most distant source of the river. From that point, Quebrada [[Carhuasanta]] emerges from Nevado Mismi, joins Quebrada Apacheta and soon forms Río Lloqueta which becomes Río Hornillos and eventually joins the [[Apurímac River|Río Apurímac]].

A 2014 study by Americans James Contos and Nicolas Tripcevich in ''[[Area (journal)|Area]]'', a peer-reviewed journal of the [[Royal Geographical Society]], however, identifies the most distant source of the Amazon as actually being in the [[Mantaro River|Río Mantaro]] drainage.<ref name="ContosTripcevich" /> A variety of methods were used to compare the lengths of the Mantaro river vs. the Apurímac river from their most distant source points to their confluence, showing the longer length of the Mantaro. Then distances from [[Lake Junin|Lago Junín]] to several potential source points in the uppermost Mantaro river were measured, which enabled them to determine that the Cordillera Rumi Cruz was the most distant source of water in the Mantaro basin (and therefore in the entire Amazon basin). The most accurate measurement method was direct GPS measurement obtained by kayak descent of each of the rivers from their source points to their confluence (performed by Contos). Obtaining these measurements was difficult given the [[International Scale of River Difficulty|class IV–V]] nature of each of these rivers, especially in their lower "Abyss" sections. Ultimately, they determined that the most distant point in the Mantaro drainage is nearly 80&nbsp;km farther upstream compared to Mt. Mismi in the Apurímac drainage, and thus the maximal length of the Amazon river is about 80&nbsp;km longer than previously thought. Contos continued downstream to the ocean and finished the first complete descent of the Amazon river from its newly identified source (finishing November 2012), a journey repeated by two groups after the news spread.<ref>{{cite web |url=http://blog.geographydirections.com/2014/04/03/redefining-the-upper-amazon-river |last=Contos |first=James (Rocky) |title=Redefining the Upper Amazon River |website=Geography Directions |date=3 April 2014 |access-date=15 July 2017 |url-status=live |archive-url=https://web.archive.org/web/20170312152411/https://blog.geographydirections.com/2014/04/03/redefining-the-upper-amazon-river/ |archive-date=12 March 2017}}</ref>

After about {{cvt|700|km|mi}}, the Apurímac then joins Río Mantaro to form the Ene, which joins the Perene to form the Tambo, which joins the [[Urubamba River]] to form the Ucayali. After the confluence of Apurímac and Ucayali, the river leaves Andean terrain and is surrounded by [[floodplain]]. From this point to the confluence of the Ucayali and the Marañón, some {{cvt|1600|km|sp=us}}, the forested banks are just above the water and are inundated long before the river attains its maximum flood stage.{{sfn|Church|1911|p=789}} The low river banks are interrupted by only a few hills, and the river enters the enormous [[Amazon rainforest]].

=== The Upper Amazon or Solimões ===
[[File:Amazonas, Iquitos - Leticia, Kolumbien (11472506936).jpg|thumb|Amazon River near [[Iquitos]], Peru]]

Although the Ucayali–Marañón confluence is the point at which most geographers place the beginning of the Amazon River proper, in Brazil the river is known at this point as the ''[[Solimões]] das Águas''. The river systems and flood plains in Brazil, Peru, Ecuador, Colombia, and Venezuela, whose waters drain into the ''Solimões'' and its tributaries, are called the "Upper Amazon".

The Amazon proper runs mostly through Brazil and Peru, and is part of the border between Colombia and Peru. It has a series of major tributaries in [[Colombia]], [[Ecuador]] and [[Peru]], some of which flow into the [[Marañón River|Marañón]] and [[Ucayali]], and others directly into the Amazon proper. These include rivers [[Putumayo River|Putumayo]], [[Caquetá River|Caquetá]], [[Vaupés River|Vaupés]], [[Rio Negro (Amazon)|Guainía]], [[Morona]], [[Pastaza River|Pastaza]], Nucuray, Urituyacu, [[Chambira River|Chambira]], [[Tigre River|Tigre]], [[Nanay River|Nanay]], [[Napo River|Napo]], and [[Huallaga River|Huallaga]].

At some points, the river divides into [[anabranch]]es, or multiple channels, often very long, with inland and lateral [[Stream channel|channels]], all connected by a complicated system of natural canals, cutting the low, flat ''igapó'' lands, which are never more than {{cvt|5|m|sp=us}} above low river, into many islands.{{sfn|Church|1911|p=788}}

From the town of Canaria at the great bend of the Amazon to the Negro, vast areas of land are submerged at high water, above which only the upper part of the trees of the sombre forests appear. Near the mouth of the Rio Negro to Serpa, nearly opposite the river Madeira, the banks of the Amazon are low, until approaching Manaus, they rise to become rolling hills.{{sfn|Church|1911|p=789}}

=== The Lower Amazon ===
[[File:Manaus Encontro das aguas 10 2006 103 8x6.jpg|thumb|[[Meeting of Waters]]; the [[confluence]] of [[Rio Negro (Amazon)|Rio Negro]] (blue) and [[Solimões|Rio Solimões]] (sandy) near [[Manaus]], Brazil]]
[[File:Rio Solimoes and Rio Negro.JPG|thumb|Water samples of the [[Solimões]] (right) and [[Rio Negro (Amazon)|Rio Negro]] (left)]]

The Lower Amazon begins where the darkly colored waters of the Rio Negro meets the sandy-colored [[Solimões|Rio Solimões]] (the upper Amazon), and for over {{cvt|6|km|sp=us}} these waters [[Meeting of Waters|run side by side without mixing]]. At Óbidos, a bluff {{cvt|17|m|sp=us}} above the river is backed by low hills. The lower Amazon seems to have once been a [[bay|gulf]] of the Atlantic Ocean, the waters of which washed the cliffs near Óbidos.

Only about 10% of the Amazon's water enters downstream of Óbidos, very little of which is from the northern slope of the valley. The drainage area of the Amazon basin above Óbidos city is about {{cvt|5000000|km2|sp=us}}, and, below, only about {{cvt|1000000|km2|sp=us}} (around 20%), exclusive of the {{cvt|1400000|km2|sp=us}} of the Tocantins basin.{{sfn|Church|1911|p=789}} The [[Tocantins River]] enters the southern portion of the [[Amazon delta]].

In the lower reaches of the river, the north bank consists of a series of steep, table-topped hills extending for about {{cvt|240|km|sp=us}} from opposite the mouth of the Xingu as far as [[Monte Alegre, Pará|Monte Alegre]]. These hills are cut down to a kind of [[Terrace (agriculture)|terrace]] which lies between them and the river.{{sfn|Church|1911|p=788}}

On the south bank, above the Xingu, a line of low bluffs bordering the floodplain extends nearly to [[Santarém, Brazil|Santarém]] in a series of gentle curves before they bend to the southwest, and, abutting upon the lower Tapajós, merge into the bluffs which form the terrace margin of the Tapajós river valley.{{sfn|Church|1911|pp=788–89}}

=== Mouth ===
[[File:Amazon-river-delta-NASA.jpg|thumb|Satellite image of the mouth of the Amazon River, from the north looking south]]

[[Belém]] is the major city and port at the mouth of the river at the Atlantic Ocean. The definition of where exactly the mouth of the Amazon is located, and how wide it is, is a matter of dispute, because of the area's peculiar geography. The [[Pará River|Pará]] and the Amazon are connected by a series of river channels called ''furos'' near the town of [[Breves, Pará|Breves]]; between them lies [[Marajó]], the world's largest combined river/sea island.

If the Pará river and the Marajó island ocean frontage are included, the Amazon [[estuary]] is some {{cvt|325|km|sp=us}} wide.<ref name=guo /> In this case, the width of the mouth of the river is usually measured from Cabo Norte, the cape located straight east of [[Pracuúba]] in the Brazilian state of [[Amapá]], to Ponta da Tijoca near the town of [[Curuçá]], in the state of [[Pará]].

A more conservative measurement excluding the Pará river estuary, from the mouth of the [[Araguari River (Amapá)|Araguari River]] to Ponta do Navio on the northern coast of [[Marajó]], would still give the mouth of the Amazon a width of over {{cvt|180.|km|sp=us}}. If only the river's main channel is considered, between the islands of Curuá (state of Amapá) and Jurupari (state of Pará), the width falls to about {{cvt|15|km|sp=us}}.

The plume generated by the river's discharge covers up to 1.3 million km<sup>2</sup> and is responsible for muddy bottoms influencing a wide area of the tropical north Atlantic in terms of salinity, pH, light penetration, and sedimentation.<ref name="auto" />

=== Lack of bridges ===
There are no [[bridge]]s across the entire width of the river.<ref>{{cite web |url=http://encarta.msn.com/encyclopedia_761571466/Amazon_(river).html |title=Amazon (river) |publisher=Microsoft Encarta Online Encyclopedia |edition=2007 |access-date=12 August 2007 |archive-url=https://web.archive.org/web/20080306073804/http://encarta.msn.com/encyclopedia_761571466/Amazon_%28river%29.html |archive-date=6 March 2008}}</ref> This is not because the river would be too wide to bridge; for most of its length, engineers could build a bridge across the river easily. For most of its course, the river flows through the Amazon Rainforest, where there are very few roads and cities. Most of the time, the crossing can be done by a [[ferry]]. The [[Manaus Iranduba Bridge]] linking the cities of Manaus and Iranduba spans the [[Rio Negro (Amazon)|Rio Negro]], the second-largest tributary of the Amazon, just before their confluence.

=== Dispute regarding length ===
[[File:Amazon River Taxi.jpg|thumb|River taxi in Peru]]
{{see also|Coastline paradox}}

While debate as to whether the Amazon or the [[Nile]] is the world's longest river has gone on for many years, the historic consensus of geographic authorities has been to regard the Amazon as the second longest river in the world, with the Nile being the longest. However, the Amazon has been reported as being anywhere between {{cvt|6275|km|sp=us}} and {{cvt|6992|km|sp=us}} long.<ref name=liu-etal-river-length /> It is often said to be "at least" {{cvt|6575|km|sp=us}} long.<ref name=britannica-amazon /> The Nile is reported to be anywhere from {{cvt|5499|to|7088|km|sp=us}}.<ref name=liu-etal-river-length /> Often it is said to be "about" {{cvt|6650|km|sp=us}} long.<ref name=britannica-nile>{{cite encyclopedia |title=Nile River |encyclopedia=[[Encyclopædia Britannica]] |year=2010 |url=https://www.britannica.com/EBchecked/topic/415347/Nile-River |access-date=3 August 2010 |url-status=live |archive-url=https://web.archive.org/web/20150429130526/https://www.britannica.com/EBchecked/topic/415347/Nile-River |archive-date=29 April 2015 |df=dmy-all}}</ref> There are several factors that can affect these measurements, such as the position of the geographical source and the mouth, the scale of measurement, and the length measuring techniques (for details see also [[List of rivers by length]]).<ref name=liu-etal-river-length /><ref name=river-source />

In July 2008, the [[National Institute for Space Research|Brazilian Institute for Space Research (INPE)]] published a news article on their webpage, claiming that the Amazon River was {{cvt|140|km|sp=us}} longer than [[Nile|the Nile]]. The Amazon's length was calculated as {{cvt|6992|km|sp=us}}, taking the Apacheta Creek as its source. Using the same techniques, the length of the Nile was calculated as {{cvt|6853|km|sp=us}}, which is longer than previous estimates but still shorter than the Amazon. The results were reached by measuring the Amazon downstream to the beginning of the tidal estuary of ''Canal do Sul'' and then, after a sharp turn back, following tidal canals surrounding the isle of Marajó and finally including the marine waters of the ''Río Pará'' bay in its entire length.<ref name=inpe /><ref name=britannica-amazon-length /> According to an earlier article on the webpage of [[National Geographic|the National Geographic]], the Amazon's length was calculated as {{cvt|6800|km|sp=us}} by a Brazilian scientist. In June 2007, [[Guido Gelli]], director of science at the [[Brazilian Institute of Geography and Statistics]] (IBGE), told London's [[The Daily Telegraph|Telegraph]] Newspaper that it could be considered that the Amazon was the longest river in the world.<ref name=Roach/> However, according to the above sources, none of the two results was published, and questions were raised about the researchers' methodology. In 2009, a [[Scholarly peer review|peer-reviewed]] article, was published, concluding that the Nile is longer than the Amazon by stating a length of {{cvt|7088|km|sp=us}} for the Nile and {{cvt|6575|km|sp=us}} for the Amazon, measured by using a combination of satellite image analysis and field investigations to the source regions.<ref name="liu-etal-river-length" />
According to the [[Encyclopædia Britannica]], the final length of the Amazon remains open to interpretation and continued debate.<ref name=britannica-amazon /><ref name=britannica-amazon-length />

== Watershed ==
{{Main|Amazon basin}}
The Amazon basin, the largest in the world, covers about 40% of South America, an area of approximately {{cvt|7050000|km2|sp=us}}. It drains from west to east, from [[Iquitos]] in Peru, across Brazil to the Atlantic. It gathers its waters from [[5th parallel north|5 degrees north latitude]] to [[20th parallel south|20 degrees south latitude]]. Its most remote sources are found on the inter-[[Andes|Andean]] plateau, just a short distance from the [[Pacific Ocean]].{{sfn|Church|1911|p=784}}

The Amazon River and its tributaries are characterised by extensive forested areas that become flooded every rainy season. Every year, the river rises more than {{cvt|9|m|sp=us}}, flooding the surrounding forests, known as ''[[Freshwater swamp forest|várzea]]'' ("flooded forests"). The Amazon's flooded forests are the most extensive example of this habitat type in the world.<ref name=wwf>{{cite web |title=Amazon River and Flooded Forests |publisher=[[World Wide Fund for Nature]] |url=http://www.nationalgeographic.com/wildworld/profiles/g200/g147.html |access-date=4 August 2010 |archive-url=https://web.archive.org/web/20080312074026/http://www.nationalgeographic.com/wildworld/profiles/g200/g147.html |archive-date=12 March 2008 |df=dmy-all}}</ref> In an average [[dry season]], {{cvt|110000|km2|sp=us}} of land are water-covered, while in the [[wet season]], the flooded area of the Amazon basin rises to {{cvt|350000|km2|sp=us}}.<ref name=guo>{{cite book |last=Guo |first=Rongxing |title=Territorial Disputes and Resource Management: A Global Handbook |year=2006 |publisher=Nova |isbn=978-1-60021-445-5 |url=https://books.google.com/books?id=z5Le627xQLgC&pg=PA44 |page=44 |url-status=live |archive-url=https://web.archive.org/web/20151015200335/https://books.google.com/books?id=z5Le627xQLgC&pg=PA44 |archive-date=15 October 2015 |df=dmy-all}}</ref>

The quantity of water released by the Amazon to the Atlantic Ocean is enormous: up to {{cvt|300000|m3/s|sp=us}} in the rainy season, with an average of {{cvt|209000|m3/s|sp=us}} from 1973 to 1990.<ref>{{cite web |url=http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/colloques2/42687.pdf |last=Molinier M |display-authors=et al |title=Hydrologie du Bassin de l'Amazone |date=22 November 1993 |access-date=16 July 2017 |language=fr |url-status=live |archive-url=https://web.archive.org/web/20161007151725/http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/colloques2/42687.pdf |archive-date=7 October 2016}}</ref> The Amazon is responsible for about 20% of the Earth's [[freshwater|fresh water]] entering the ocean.<ref name=wwf /> The river pushes a vast plume of fresh water into the ocean. The plume is about {{cvt|400|km|sp=us}} long and between {{cvt|100|and|200|km|sp=us}} wide. The fresh water, being lighter, flows on top of the seawater, diluting the [[salinity]] and altering the colour of the ocean surface over an area up to {{cvt|2500000|km2|sp=us}} in extent. For centuries ships have reported fresh water near the Amazon's mouth yet well out of sight of land in what otherwise seemed to be the open ocean.<ref name=smith />

Despite this, the Atlantic has sufficient wave and tidal energy to carry most of the Amazon's [[sediment]]s out to sea, thus the Amazon does not form a significant [[river delta]]. The great deltas of the world are all in relatively protected bodies of water, while the Amazon empties directly into the turbulent Atlantic.<ref name=Penn />

There is a natural water union between the Amazon and the [[Orinoco]] basins, the so-called [[Casiquiare canal]]. The Casiquiare is a river [[distributary]] of the upper Orinoco, which flows southward into the Rio Negro, which in turn flows into the Amazon. The Casiquiare is the largest river on earth that links two major river systems, a so-called [[River bifurcation|bifurcation]].

== Discharge ==

Average discharge at the [[Amazon Delta|estuary]]; Period from 2003 to 2015: {{cvt|7,200|km3/year|m3/s}}<ref name="Amazon basin water resources observation service">{{cite web |url=https://hybam.obs-mip.fr/ |title=Amazon basin water resources observation service |access-date=23 February 2023 |archive-date=8 September 2023 |archive-url=https://web.archive.org/web/20230908072837/https://hybam.obs-mip.fr/ |url-status=live }}</ref><ref name="Basin-Scale River Runoff Estimation From GRACE Gravity Satellites, Climate Models, and in Situ Observations: A Case study in the Amazon Basin">{{cite journal |title=Basin-Scale River Runoff Estimation From GRACE Gravity Satellites, Climate Models, and in Situ Observations: A Case study in the Amazon Basin |last1=Jianli |first1=Chen |last2=Byron |first2=Tapley |last3=Matt |first3=Rodell |last4=Ki-Weon |first4=Seo |last5=Clark |first5=Wilson |last6=Bridget K. |first6=Scanlon |last7=Yadu |first7=Pokhrel |journal=Water Resources Research |year=2020 |volume=56 |issue=10 |doi=10.1029/2020WR028032 |bibcode=2020WRR....5628032C |s2cid=224933962}}</ref>
{| class="wikitable" style="text-align:center;"
 |-
!Year
! (km<sup>3</sup>)
 ! (m<sup>3</sup>/s)
 !Year
!(km<sup>3</sup>)
!(m<sup>3</sup>/s)
|-
|2003
|6,470
|205,000
|2010
|6,464
|205,000
|-
|2004
|6,747
|214,000
|2011
|7,378
|234,000
|-
|2005
|6,522
|207,000
|2012
|7,513
|238,000
|-
|2006
|7,829
|248,000
|2013
|7,288
|231,000
|-
|2007
|7,133
|226,000
|2014
|7,674
|243,000
|-
|2008
|7,725
|245,000
|2015
|6,657
|211,000
|-
|2009
|8,200
|260,000
| colspan="3" |
|}
===[[Amazon Delta]]===
Water discharge of the Amazon with [[Tocantins River]]. Complete series from starting 1920.
{| class="wikitable mw-collapsible mw-collapsed" style="text-align:center;"
|+Average discharge (10<sup>3</sup> m<sup>3</sup>/s)
|-
!Year
!Discharge
! rowspan="49" |
!Year
!Discharge
|-
|2015
|210.9
|1967
|231
|-
|2014
|243.2
|1966
|237
|-
|2013
|230.9
|1965
|232
|-
|2012
|238.1
|1964
|218
|-
|2011
|233.8
|1963
|240
|-
|2010
|204.8
|1962
|220
|-
|2009
|260
|1961
|229
|-
|2008
|244.8
|1960
|207
|-
|2007
|226
|1959
|236
|-
|2006
|248.1
|1958
|229
|-
|2005
|206.7
|1957
|210
|-
|2004
|213.8
|1956
|230
|-
|2003
|205
|1955
|233
|-
|2002
|214
|1954
|238
|-
|2001
|216
|1953
|234
|-
|2000
|234
|1952
|223
|-
|1999
|212
|1951
|227
|-
|1998
|149
|1950
|230
|-
|1997
|201
|1949
|213
|-
|1996
|212
|1948
|228
|-
|1995
|195
|1947
|210
|-
|1994
|240
|1946
|222
|-
|1993
|218
|1945
|192
|-
|1992
|156
|1944
|220
|-
|1991
|218
|1943
|208
|-
|1990
|198
|1942
|200
|-
|1989
|230
|1941
|203
|-
|1988
|200
|1940
|208
|-
|1987
|180
|1939
|229
|-
|1986
|208
|1938
|200
|-
|1985
|240
|1937
|188
|-
|1984
|270
|1936
|183
|-
|1983
|186
|1935
|215
|-
|1982
|236
|1934
|230
|-
|1981
|202
|1933
|200
|-
|1980
|190
|1932
|214
|-
|1979
|224
|1931
|190
|-
|1978
|233
|1930
|209
|-
|1977
|232
|1929
|201
|-
|1976
|239
|1928
|208
|-
|1975
|242
|1927
|220
|-
|1974
|242
|1926
|202
|-
|1973
|224
|1925
|210
|-
|1972
|238
|1924
|222
|-
|1971
|235
|1923
|210
|-
|1970
|220
|1922
|219
|-
|1969
|211
|1921
|224
|-
|1968
|210
|1920
|200
|-
| colspan="5" |Source:<ref name="Fresh Surface Water">{{cite book|url=https://books.google.com/books/about/Fresh_Surface_Water_Volume_I.html?hl=hu&id=nleHCwAAQBAJ#v=onepage&q=orinoco%20river%20m3%2Fs&f=true|title=Fresh Surface Water|last=James|first=C. I. Dooge|isbn=978-1-84826-011-5|publisher=UNESCO|location=Oxford, United Kingdom|year=2009}}</ref><ref name="ANEEL — Agência Nacional de Energia Elétrica">{{cite web|url=https://www.gov.br/aneel/pt-br|title=ANEEL — Agência Nacional de Energia Elétrica}}</ref><ref name="Amazon basin water resources observation service">{{cite web |url=https://hybam.obs-mip.fr/ |title=Amazon basin water resources observation service |access-date=23 February 2023 |archive-date=8 September 2023 |archive-url=https://web.archive.org/web/20230908072837/https://hybam.obs-mip.fr/ |url-status=live }}</ref><ref name="Basin-Scale River Runoff Estimation From GRACE Gravity Satellites, Climate Models, and in Situ Observations: A Case study in the Amazon Basin">{{cite journal |title=Basin-Scale River Runoff Estimation From GRACE Gravity Satellites, Climate Models, and in Situ Observations: A Case study in the Amazon Basin |last1=Jianli |first1=Chen |last2=Byron |first2=Tapley |last3=Matt |first3=Rodell |last4=Ki-Weon |first4=Seo |last5=Clark |first5=Wilson |last6=Bridget K. |first6=Scanlon |last7=Yadu |first7=Pokhrel |journal=Water Resources Research |year=2020 |volume=56 |issue=10 |doi=10.1029/2020WR028032 |bibcode=2020WRR....5628032C |s2cid=224933962}}</ref> 
|}
{| class="wikitable mw-collapsible mw-collapsed" style="text-align:center;"
|+Monthly average discharge (m<sup>3</sup>/s)
! rowspan="2" |Month
! colspan="3" |Discharge
|-
![[Amazon River|Amazon]]
! rowspan="13" |
![[Pará River|Pará]]
|-
|JAN
|126,100
|7,300
|-
|FEB
|177,100
|14,200
|-
|MAR
|186,300
|18,200
|-
|APR
|201,300
|28,700
|-
|MAY
|236,600
|38,700
|-
|JUN
|275,600
|40,500
|-
|JUL
|296,900
|32,600
|-
|AUG
|288,500
|14,500
|-
|SEP
|262,500
|6,100
|-
|OCT
|227,000
|2,500
|-
|NOV
|118,800
|1,000
|-
|DEC
|82,400
|1,000
|-
| colspan="4" |
|-
|'''''Average'''''
|'''''206,600'''''
|
|'''''17,100'''''
|-
| colspan="4" |Source:<ref>{{cite book|last1=Charles J.|first1=Vörösmarty|last2=Berrien|first2=Moore|last3=Annette L.|first3=Grace|last4=M. Patricia|first4=Gildea|url=https://gmao.gsfc.nasa.gov/gmaoftp/sarith/ROUTING_MODEL/docs/Vorosmarty_1989.pdf|title=CONTINENTAL SCALE MODELS OF WATER BALANCE AND FLUVIAL TRANSPORT: AN APPLICATIONS TO SOUTH AMERICA|volume=3|pages=241–265|year=1989}}</ref>
|}
===Santarém===
Water discharge of the Amazon River at the [[Santarém, Pará|Santarém]] gauging station.
{| class="wikitable mw-collapsible mw-collapsed" style="text-align:center;"
|+Average, minimum and maximum discharge (1998/01/01—2024/12/31)
 ! rowspan="2" |Year
! colspan="3" |Discharge (m<sup>3</sup>/s)
|-
!Min
!Mean
!Max
|-
|1998
|69,202
|''175,218''
|278,306
|-
|1999
|73,921
|''182,266''
|270,080
|-
|2000
|73,306
|''171,899''
|275,060
|-
|2001
|67,300
|''173,517''
|268,820
|-
|2002
|92,711
|''207,186''
|296,805
|-
|2003
|100,473
|''182,767''
|252,626
|-
|2004
|100,986
|''184,880''
|265,644
|-
|2005
|67,464
|''172,411''
|280,340
|-
|2006
|91,126
|''192,500''
|301,860
|-
|2007
|73,256
|''192,715''
|309,478
|-
|2008
|101,146
|''198,128''
|316,669
|-
|2009
|76,598
|''204,920''
|303,192
|-
|2010
|72,101
|''172,255''
|255,208
|-
|2011
|65,803
|''155,030''
|256,798
|-
|2012
|50,070
|''194,883''
|323,680
|-
|2013
|55,108
|''206,295''
|305,526
|-
|2014
|151,997
|''235,390''
|338,905
|-
|2015
|70,119
|''261,580''
|378,767
|-
|2016
|69,995
|''230,788''
|367,296
|-
|2017
|104,111
|''223,193''
|352,935
|-
|2018
|95,376
|''262,946''
|386,022
|-
|2019
|96,260
|''260,664''
|382,840
|-
|2020
|72,955
|''234,725''
|388,213
|-
|2021
|94,903
|''262,264''
|376,740
|-
|2022
|101,693
|''259,902''
|405,999
|-
|2023
|46,130
|''217,551''
|370,109
|-
|2024
|48,898
|''198,627''
|350,570
|-
| colspan="4" |Source: ''The Flood Observatory''<ref name="River and Reservoir Watch Version 4.5-146">{{cite web |url=https://floodobservatory.colorado.edu/SiteDisplays/146data.htm |title=River and Reservoir Watch Version 4.5-146 |access-date=8 October 2023 |archive-date=14 October 2023 |archive-url=https://web.archive.org/web/20231014093159/https://floodobservatory.colorado.edu/SiteDisplays/146data.htm |url-status=live }}</ref><ref name="River and Reservoir Watch Version 4.5-148" />
|}
===Óbidos===
Water discharge of the Amazon River at the [[Óbidos, Pará|Óbidos]] gauging station. Complete series from starting 1903.
{| class="wikitable mw-collapsible mw-collapsed" style="text-align:center;"
|+Average, minimum and maximum discharge (m<sup>3</sup>/s)
|-
!Year
!Min
!''Mean''
!Max
! rowspan="62" |
!Year
!Min
!''Mean''
!Max
|-
|2023
|61,000
|''154,988''
|333,700
|1962
|92,800
|''167,864''
|245,100
|-
|2022
|77,200
|''162,990''
|375,200
|1961
|77,800
|''153,577''
|221,400
|-
|2021
|106,700
|''177,000''
|353,800
|1960
|99,300
|''161,502''
|230,300
|-
|2020
|92,800
|''170,912''
|344,800
|1959
|103,000
|''159,604''
|231,900
|-
|2019
|87,900
|''162,810''
|352,300
|1958
|73,700
|''153,243''
|234,300
|-
|2018
|92,300
|''180,232''
|336,200
|1957
|84,200
|''156,814''
|227,200
|-
|2017
|93,300
|''181,025''
|352,100
|1956
|123,700
|''160,720''
|236,100
|-
|2016
|87,600
|''159,308''
|347,500
|1955
|80,100
|''166,970''
|252,700
|-
|2015
|120,400
|''186,731''
|355,300
|1954
|94,400
|''173,000''
|253,300
|-
|2014
|113,000
|''196,940''
|321,700
|1953
|90,600
|''189,070''
|394,000
|-
|2013
|117,400
|''193,573''
|301,200
|1952
|94,100
|''158,150''
|317,000
|-
|2012
|87,900
|''192,292''
|370,000
|1951
|101,900
|''161,110''
|283,000
|-
|2011
|80,600
|''176,523''
|242,800
|1950
|78,200
|''166,078''
|368,000
|-
|2010
|77,100
|''165,902''
|254,000
|1949
|116,700
|''171,323''
|356,000
|-
|2009
|85,800
|''198,590''
|291,040
|1948
|78,400
|''159,946''
|288,000
|-
|2008
|87,700
|''193,072''
|280,800
|1947
|109,200
|''165,500''
|213,000
|-
|2007
|95,500
|''174,068''
|278,600
|1946
|93,700
|''172,012''
|283,000
|-
|2006
|88,400
|''184,690''
|279,200
|1945
|88,200
|''148,566''
|244,000
|-
|2005
|72,800
|''161,830''
|273,500
|1944
|96,800
|''174,608''
|309,000
|-
|2004
|86,400
|''165,096''
|218,500
|1943
|88,200
|''161,866''
|260,000
|-
|2003
|90,400
|''170,802''
|248,000
|1942
|93,200
|''154,500''
|236,000
|-
|2002
|93,700
|''177,493''
|265,400
|1941
|86,800
|''156,379''
|231,000
|-
|2001
|74,400
|''175,527''
|257,000
|1940
|119,000
|''157,708''
|213,000
|-
|2000
|87,900
|''181,146''
|258,500
|1939
|126,000
|''174,625''
|281,000
|-
|1999
|75,300
|''185,737''
|299,700
|1938
|94,000
|''154,412''
|257,000
|-
|1998
|75,000
|''149,382''
|268,200
|1937
|82,800
|''143,237''
|212,000
|-
|1997
|72,400
|''169,129''
|265,800
|1936
|81,900
|''139,133''
|212,000
|-
|1996
|108,600
|''180,190''
|251,200
|1935
|82,500
|''169,612''
|299,000
|-
|1995
|74,600
|''151,499''
|259,300
|1934
|129,000
|''173,166''
|292,000
|-
|1994
|106,000
|''200,335''
|296,000
|1933
|83,600
|''154,658''
|256,000
|-
|1993
|106,000
|''181,290''
|262,000
|1932
|93,400
|''165,096''
|260,000
|-
|1992
|91,800
|''138,555''
|194,600
|1931
|88,500
|''146,354''
|230,000
|-
|1991
|82,500
|''169,444''
|248,000
|1930
|98,400
|''158,679''
|243,000
|-
|1990
|83,400
|''167,368''
|235,000
|1929
|86,600
|''156,037''
|276,000
|-
|1989
|120,000
|''206,941''
|346,000
|1928
|92,600
|''151,000''
|284,000
|-
|1988
|92,300
|''165,547''
|228,000
|1927
|119,600
|''159,940''
|231,900
|-
|1987
|92,200
|''164,552''
|231,000
|1926
|70,700
|''111,513''
|151,400
|-
|1986
|125,000
|''182,247''
|244,000
|1925
|96,000
|''171,547''
|250,800
|-
|1985
|113,000
|''159,840''
|190,000
|1924
|95,500
|''142,416''
|202,900
|-
|1984
|105,000
|''173,350''
|259,000
|1923
|91,500
|''178,802''
|246,300
|-
|1983
|86,100
|''140,892''
|179,000
|1922
|129,000
|''187,619''
|279,200
|-
|1982
|96,100
|''186,200''
|302,000
|1921
|93,000
|''174,784''
|268,900
|-
|1981
|88,300
|''149,806''
|191,000
|1920
|116,900
|''175,452''
|255,200
|-
|1980
|91,200
|''142,473''
|176,000
|1919
|88,700
|''148,443''
|209,000
|-
|1979
|91,500
|''169,696''
|267,000
|1918
|103,000
|''170,543''
|260,200
|-
|1978
|115,300
|''178,293''
|257,000
|1917
|94,400
|''136,835''
|215,600
|-
|1977
|119,700
|''176,834''
|269,000
|1916
|70,100
|''144,984''
|213,800
|-
|1976
|95,400
|''192,734''
|327,000
|1915
|86,700
|''159,604''
|235,700
|-
|1975
|106,000
|''197,545''
|307,000
|1914
|94,600
|''171,882''
|253,600
|-
|1974
|131,600
|''193,870''
|280,000
|1913
|131,000
|''178,132''
|252,700
|-
|1973
|123,000
|''179,537''
|250,000
|1912
|112,500
|''135,047''
|185,700
|-
|1972
|109,000
|''182,624''
|264,000
|1911
|83,200
|''159,710''
|232,100
|-
|1971
|121,400
|''187,121''
|288,000
|1910
|102,000
|''154,024''
|237,100
|-
|1970
|84,500
|''163,232''
|239,000
|1909
|76,400
|''170,095''
|274,800
|-
|1969
|89,200
|''156,720''
|210,000
|1908
|102,100
|''176,793''
|267,700
|-
|1968
|113,000
|''148,220''
|202,000
|1907
|84,600
|''140,184''
|224,800
|-
|1967
|89,000
|''162,506''
|227,000
|1906
|69,600
|''142,194''
|202,200
|-
|1966
|87,300
|''143,868''
|207,400
|1905
|93,500
|''141,524''
|203,900
|-
|1965
|85,400
|''144,650''
|215,600
|1904
|93,300
|''174,561''
|262,500
|-
|1964
|103,500
|''136,612''
|202,300
|1903
|82,800
|''148,220''
|230,000
|-
|1963
|72,800
|''141,190''
|226,800
| colspan="4" |
|-
| colspan="9" |Source:<ref name="Amazon basin water resources observation service"/><ref name="Basin-Scale River Runoff Estimation From GRACE Gravity Satellites, Climate Models, and in Situ Observations: A Case study in the Amazon Basin"/><ref name="ANEEL — Agência Nacional de Energia Elétrica">{{cite web|url=https://www.gov.br/aneel/pt-br|title=ANEEL — Agência Nacional de Energia Elétrica}}</ref><ref name="Amazon basin water resources observation service">{{cite web |url=https://hybam.obs-mip.fr/ |title=Amazon basin water resources observation service |access-date=23 February 2023 |archive-date=8 September 2023 |archive-url=https://web.archive.org/web/20230908072837/https://hybam.obs-mip.fr/ |url-status=live }}</ref>
|}
{| class="wikitable mw-collapsible mw-collapsed" style="text-align:center;"
|+Monthly average discharge (1968—2022)
|-
!Month
!Discharge
(m<sup>3</sup>/s)
|-
|JAN
|137,749
|-
|FEB
|163,264
|-
|MAR
|186,036
|-
|APR
|206,989
|-
|MAY
|220,717
|-
|JUN
|221,055
|-
|JUL
|209,765
|-
|AUG
|186,655
|-
|SEP
|149,159
|-
|OCT
|112,032
|-
|NOV
|102,544
|-
|DEC
|114,746
|-
| colspan="2" |
|-
| colspan="2" |Source:<ref name="Relatório Técnico">{{cite book|url=https://pos.uea.edu.br/data/area/dissertacao/download/61-32.pdf|title=Relatório Técnico|last=Gabriellen|first=Yasmine de Oliveira|page=48|isbn=978-65-5872-652-4|year=2023}}</ref>
|}
===Itacoatiara===
Water discharge of the Amazon River at the [[Itacoatiara, Amazonas|Itacoatiara]] gauging station.
{| class="wikitable mw-collapsible mw-collapsed" style="text-align:center;"
|+Average, minimum and maximum discharge (1998/01/01—2024/12/31)
 ! rowspan="2" |Year
! colspan="3" |Discharge (m<sup>3</sup>/s)
|-
!Min
!Mean
!Max
|-
|1998
|41,312
|''139,002''
|240,396
|-
|1999
|64,130
|''171,662''
|288,869
|-
|2000
|52,870
|''161,345''
|261,176
|-
|2001
|30,670
|''157,286''
|256,627
|-
|2002
|67,979
|''164,171''
|252,425
|-
|2003
|82,556
|''149,274''
|228,998
|-
|2004
|66,183
|''139,926''
|223,929
|-
|2005
|57,598
|''145,002''
|258,383
|-
|2006
|61,265
|''168,975''
|268,108
|-
|2007
|74,679
|''161,393''
|238,839
|-
|2008
|71,572
|''168,065''
|259,841
|-
|2009
|59,298
|''166,100''
|275,544
|-
|2010
|53,715
|''128,035''
|215,638
|-
|2011
|42,192
|''129,710''
|230,293
|-
|2012
|29,489
|''172,103''
|291,537
|-
|2013
|51,341
|''172,201''
|286,872
|-
|2014
|85,599
|''192,462''
|324,191
|-
|2015
|66,094
|''221,843''
|339,832
|-
|2016
|41,063
|''167,746''
|311,494
|-
|2017
|60,218
|''205,382''
|329,771
|-
|2018
|65,629
|''202,838''
|316,291
|-
|2019
|96,549
|''227,078''
|340,215
|-
|2020
|44,698
|''214,586''
|352,671
|-
|2021
|85,862
|''236,885''
|354,795
|-
|2022
|56,758
|''214,763''
|337,412
|-
|2023
|38,496
|''173,676''
|304,336
|-
|2024
|27,088
|''156,907''
|297,641
|-
| colspan="4" |Source: ''The Flood Observatory''<ref name="River and Reservoir Watch Version 4.5-146">{{cite web |url=https://floodobservatory.colorado.edu/SiteDisplays/146data.htm |title=River and Reservoir Watch Version 4.5-146 |access-date=8 October 2023 |archive-date=14 October 2023 |archive-url=https://web.archive.org/web/20231014093159/https://floodobservatory.colorado.edu/SiteDisplays/146data.htm |url-status=live }}</ref><ref name="River and Reservoir Watch Version 4.5-148" />
|}
{| class="wikitable mw-collapsible mw-collapsed" style="text-align:center;"
|+Monthly average discharge (2008—2021)
|-
!Month
!Discharge
(m<sup>3</sup>/s)
|-
|JAN
|122,910
|-
|FEB
|146,170
|-
|MAR
|170,972
|-
|APR
|185,403
|-
|MAY
|198,166
|-
|JUN
|200,022
|-
|JUL
|190,811
|-
|AUG
|170,101
|-
|SEP
|133,948
|-
|OCT
|99,706
|-
|NOV
|93,029
|-
|DEC
|103,054
|-
| colspan="2" |
|-
| colspan="2" |Source:<ref name="Relatório Técnico">{{cite book|url=https://pos.uea.edu.br/data/area/dissertacao/download/61-32.pdf|title=Relatório Técnico|last=Gabriellen|first=Yasmine de Oliveira|page=48|isbn=978-65-5872-652-4|year=2023}}</ref>
|}

== Sediment load ==
[[Stream load|Sediment load]] (S - 754 x 10<sup>6</sup> ton/year) at [[Óbidos, Pará|Óbidos]] gauge station (period from 1996 to 2007).
{| class="wikitable" style="text-align:center;"
 |-
!Year
! S
! rowspan="7" |
!Year
! S
|-
|1996
|672
|2002
|802
|-
|1997
|691
|2003
|832
|-
|1998
|652
|2004
|807
|-
|1999
|732
|2005
|797
|-
|2000
|692
|2006
|742
|-
|2001
|787
|2007
|842
|-
| colspan="5" |Source:<ref name="The Amazon-influenced high mud-supply shores of South America: A review of mud bank-shoreline interactions">{{cite web |url=https://www.researchgate.net/publication/280785397 |title=The Amazon-influenced high mud-supply shores of South America: A review of mud bank-shoreline interactions |last1=Edward |first1=Anthony |last2=Antoine |first2=Gandel |last3=Nicolas |first3=Goatiot |last4=Christophe |first4=Proisy |last5=Mead A. |first5=Allison |last6=Franck |first6=Dolique |last7=F. |first7=Fromard |year=2010}}</ref>
|}

== Flooding ==
[[File:Amazon-river-NASA.jpg|thumb|[[NASA]] satellite image of a flooded portion of the river]]

Not all of the Amazon's tributaries flood at the same time of the year. Many branches begin flooding in November and might continue to rise until June. The rise of the Rio Negro starts in February or March and begins to recede in June. The Madeira River rises and falls two months earlier than most of the rest of the Amazon river.

The depth of the Amazon between [[Manacapuru]] and [[Óbidos, Brazil|Óbidos]] has been calculated as between {{cvt|20|and|26|m|sp=us}}. At Manacapuru, the Amazon's water level is only about {{cvt|24|m|sp=us}} above [[Sea level|mean sea level]]. More than half of the water in the Amazon downstream of Manacapuru is below sea level.<ref name=junk>{{cite book |last=Junk |first=Wolfgang J. |title=The Central Amazon Floodplain: Ecology of a Pulsing System |year=1997 |publisher=Springer |isbn=978-3-540-59276-1 |url=https://books.google.com/books?id=1eMWTwL4rbEC&pg=PA44 |page=44 |url-status=live |archive-url=https://web.archive.org/web/20150908072225/https://books.google.com/books?id=1eMWTwL4rbEC&pg=PA44 |archive-date=8 September 2015 |df=dmy-all}}</ref> In its lowermost section, the Amazon's depth averages {{cvt|20|to|50|m|sp=us}}, in some places as much as {{cvt|100|m|sp=us}}.<ref name=whitton>{{cite book |last=Whitton |first=B.A. |title=River Ecology |year=1975 |publisher=University of California Press |isbn=978-0-520-03016-9 |url=https://books.google.com/books?id=q5H_1PtdvrAC&pg=PA462 |page=462 |url-status=live |archive-url=https://web.archive.org/web/20150915133552/https://books.google.com/books?id=q5H_1PtdvrAC&pg=PA462 |archive-date=15 September 2015 |df=dmy-all}}</ref>

The main river is navigable for large ocean steamers to [[Manaus]], {{cvt|1500|km|sp=us}} upriver from the mouth. Smaller ocean vessels below 9000 tons and with less than {{cvt|5.5|m|ft|sp=us}} [[Draft (hull)|draft]] can reach as far as [[Iquitos]], Peru, {{cvt|3600|km|sp=us}} from the sea. Smaller riverboats can reach {{cvt|780|km|sp=us}} higher, as far as Achual Point. Beyond that, small boats frequently ascend to the [[Pongo de Manseriche]], just above Achual Point in Peru.{{sfn|Church|1911|p=788}}

Annual flooding occurs in late northern latitude winter at high tide when the incoming waters of the [[Atlantic Ocean|Atlantic]] are funnelled into the Amazon delta. The resulting [[Undular bore#In hydraulics|undular]] [[tidal bore]] is called the ''[[pororoca]]'', with a leading wave that can be up to {{cvt|25|ft|m|order=flip|sp=us}} high and travel up to {{cvt|500|mi|km|order=flip}} inland.<ref>{{cite book |title=Environmental Geology: Facing the Challenges of Our Changing Earth |url=https://books.google.com/books?id=TFTxRdqBZCYC&pg=PA110 |pages=110–11 |first=Jon |last=Erickson |publisher=Infobase Publishing |year=2014 |access-date=25 March 2016 |isbn=978-1-4381-0963-3 |url-status=live |archive-url=https://web.archive.org/web/20170208120955/https://books.google.com/books?id=TFTxRdqBZCYC&pg=PA110 |archive-date=8 February 2017}}</ref><ref>{{cite journal |journal=Scientific American |date=1982 |first=David K. |last=Lynch |title=Tidal Bores |volume=247 |issue=4 |page=146 |doi=10.1038/scientificamerican1082-146 |bibcode=1982SciAm.247d.146L |url=http://www.thulescientific.com/TidalBores.pdf |access-date=25 March 2016 |url-status=live |archive-url=https://web.archive.org/web/20160328090911/http://thulescientific.com/TidalBores.pdf |archive-date=28 March 2016}}</ref>

== Geology ==
The Amazon River originated as a transcontinental river in the [[Miocene]] epoch between 11.8 million and 11.3 million years ago and took its present shape approximately 2.4 million years ago in the Early [[Pleistocene]].

The proto-Amazon during the [[Cretaceous]] flowed west, as part of a proto-Amazon-Congo river system, from the interior of present-day Africa when the continents were connected, forming western [[Gondwana]]. 80 million years ago, the two continents split. Fifteen million years ago, the main [[tectonic uplift]] phase of the Andean chain started. This tectonic movement is caused by the subduction of the [[Nazca Plate]] underneath the [[South American Plate]]. The rise of the Andes and the linkage of the Brazilian and [[Guayana Shield|Guyana]] bedrock shields,{{clarify|date=February 2017}} blocked the river and caused the Amazon Basin to become a vast inland sea. Gradually, this inland sea became a massive swampy, freshwater lake and the marine inhabitants adapted to life in freshwater.<ref>{{Cite web |url=https://rainforests.mongabay.com/amazon/ |title=The Amazon Rainforest |website=Mongabay |access-date=2020-02-09 |archive-url=https://web.archive.org/web/20190827231405/https://rainforests.mongabay.com/amazon/ |archive-date=27 August 2019 |url-status=live}}</ref>

Eleven to ten million years ago, waters worked through the [[sandstone]] from the west and the Amazon began to flow eastward, leading to the emergence of the Amazon rainforest. During [[glacial period]]s, sea levels dropped and the great Amazon lake rapidly drained and became a river, which would eventually become the disputed world's longest, draining the most extensive area of rainforest on the planet.<ref>{{cite journal |first1=J. |last1=Figueiredo |first2=C. |last2=Hoorn |first3=P. |last3=van der Ven |first4=E. |last4=Soares |title=Late Miocene onset of the Amazon River and the Amazon deep-sea fan: Evidence from the Foz do Amazonas Basin |journal=Geology |year=2009 |volume=37 |issue=7 |pages=619–22 |doi=10.1130/g25567a.1 |bibcode=2009Geo....37..619F |s2cid=70646688}}</ref>

Paralleling the Amazon River is a large aquifer, dubbed the [[Hamza River]], the discovery of which was made public in August 2011.<ref name="tv.ibtimes.com">{{cite web |url=http://tv.ibtimes.com/massive-river-found-flowing-beneath-the-amazon/1753.html |title=Massive River Found Flowing Beneath the Amazon |access-date=8 September 2011 |archive-url=https://archive.today/20111110171150/http://tv.ibtimes.com/massive-river-found-flowing-beneath-the-amazon/1753.html |archive-date=10 November 2011}}</ref>

== Protected areas ==
{| class="wikitable sortable mw-collapsible"
! Name
! Country
! Coordinates
! Image
! Notes
|-
| [[Allpahuayo-Mishana National Reserve]] || [[Peru]] || {{coord|3|56|S|73|33|W|display=inline}} || [[File:Crypturellus duidae.JPG|center|150px]] || {{center|<ref>{{cite web |url=http://www.sernanp.gob.pe/allpahuayo-mishana |title=Allpahuayo Mishana |publisher=Servicio Nacional de Áreas Naturales Protegidas por el Estado |language=es |url-status=live |archive-url=https://web.archive.org/web/20160913130034/http://www.sernanp.gob.pe/allpahuayo-mishana |archive-date=13 September 2016}}</ref>}}
|-
| [[Amacayacu National Park]] || [[Colombia]] || {{coord|3|29|S|72|12|W|display=inline}} || [[File:Riverguama1.jpg|center|150px]] || {{center|<ref>{{cite web |url=http://www.parquesnacionales.gov.co/portal/es/ecoturismo/region-amazonia/parque-nacional-natural-amacayacu/ |title=Parque Nacional Natural Amacayacu |publisher=Parques Nacionales Naturales de Colombia |language=es |url-status=live |archive-url=https://web.archive.org/web/20170202043446/http://www.parquesnacionales.gov.co/portal/es/ecoturismo/region-amazonia/parque-nacional-natural-amacayacu/ |archive-date=2 February 2017}}</ref>}}
|-
| [[Amazônia National Park]] || [[Brazil]] || {{coord|4|26|S|56|50|W|display=inline}} || [[File:Amazonia por Flaviz Guerra 02.jpg|center|150px]] || {{center|<ref>{{cite web |url=https://uc.socioambiental.org/en/uc/481 |title=Parna da Amazônia |publisher=Instituto Socioambiental (ISA) |url-status=live |archive-url=https://web.archive.org/web/20161030001047/http://uc.socioambiental.org/en/uc/481 |archive-date=30 October 2016}}</ref>}}
|-
| [[Anavilhanas National Park]] || [[Brazil]] || {{coord|2|23|S|60|55|W|display=inline}} || [[File:Anavilhanas2.jpg|center|150px]] || {{center|<ref>{{cite web |url=https://uc.socioambiental.org/uc/564 |title=Parna de Anavilhanas |publisher=Instituto Socioambiental (ISA) |url-status=live |archive-url=https://web.archive.org/web/20160506022242/http://uc.socioambiental.org/uc/564 |archive-date=6 May 2016}}</ref>}}
|-
|}

== Flora and fauna ==
{{see also|Biodiversity of Colombia#Amazon natural region}}

=== Flora ===
{{category see also|Flora of the Amazon|Trees of the Amazon rainforest}}

=== Fauna ===
[[File:Schwarzer Pacu Colossoma macropomum Tierpark Hellabrunn-1.jpg|thumb|The [[tambaqui]], an important species in Amazonian fisheries, breeds in the Amazon River.]]
{{see also|:Category:Fauna of the Amazon}}

More than one-third of all known species in the world live in the [[Amazon rainforest]].<ref>{{cite web |url=http://web.worldbank.org/WBSITE/EXTERNAL/NEWS/0,,contentMDK:20757099~pagePK:64257043~piPK:437376~theSitePK:4607,00.html |last=World Bank |title=Brazilian Amazon rain forest fact sheet |date=15 December 2005 |access-date=16 July 2017 |url-status=live |archive-url=https://web.archive.org/web/20140503151515/http://web.worldbank.org/WBSITE/EXTERNAL/NEWS/0,,contentMDK:20757099~pagePK:64257043~piPK:437376~theSitePK:4607,00.html |archive-date=3 May 2014 |df=dmy-all}}</ref> It is the richest tropical forest in the world in terms of [[biodiversity]].<ref name=Albert;Reis>{{cite book|date=March 2011|location=[[Berkeley, California]]|editor-last1=Albert|editor-first1=James S|editor-link1=James S. Albert|editor-last2=Reis|editor-first2=Roberto E|editor-link2=Roberto Esser dos Reis|title=Historical Biogeography of Neotropical Freshwater Fishes|url=https://www.ucpress.edu/books/historical-biogeography-of-neotropical-freshwater-fishes/hardcover|url-access=subscription|language=en-US|edition=1|publisher=[[University of California Press]]|doi=10.1525/california/9780520268685.001.0001|isbn=9780520268685|jstor=10.1525/j.ctt1pp29c|oclc=644018311|url-status=live|archive-url=https://web.archive.org/web/20241006051051/https://www.ucpress.edu/books/historical-biogeography-of-neotropical-freshwater-fishes/hardcover|archive-date=2024-10-06|access-date=2011-12-19}}</ref> In addition to thousands of species of fish, the river supports crabs, algae, and turtles.

==== Mammals ====
[[File:NOVO AIRÃO.JPG|thumb|[[Amazon river dolphin]]]]

Along with the Orinoco, the Amazon is one of the main habitats of the ''[[boto]]'', also known as the [[Amazon river dolphin]] (''Inia geoffrensis''). It is the largest species of [[river dolphin]], and it can grow to lengths of up to {{cvt|2.6|m|ft|sp=us}}. The colour of its skin changes with age; young animals are gray, but become pink and then white as they mature. The dolphins use [[Animal echolocation|echolocation]] to navigate and hunt in the river's tricky depths.<ref>{{cite web |title=Amazon River Dolphin |url=http://rainforest-alliance.org/kids/species-profiles/river-dolphin |publisher=Rainforest Alliance |access-date=20 March 2011 |url-status=live |archive-url=https://web.archive.org/web/20110301063907/http://rainforest-alliance.org/kids/species-profiles/river-dolphin |archive-date=1 March 2011}}</ref> The ''boto'' is the subject of a legend in Brazil about a [[dolphin]] that turns into a man and seduces maidens by the riverside.<ref>{{cite journal |last1=Cravalho |first1=Michael A. |title=Shameless Creatures: an Ethnozoology of the Amazon River Dolphin |journal=Ethnology |date=1999 |volume=38 |issue=1 |pages=47–58 |doi=10.2307/3774086 |jstor=3774086}}</ref>

The [[tucuxi]] (''Sotalia fluviatilis''), also a dolphin species, is found both in the rivers of the Amazon basin and in the coastal waters of South America. The [[Amazonian manatee]] (''Trichechus inunguis''), also known as "seacow", is found in the northern Amazon River basin and its tributaries. It is a mammal and a herbivore. Its population is limited to freshwater habitats, and, unlike other manatees, it does not venture into saltwater. It is classified as vulnerable by the [[International Union for Conservation of Nature]].<ref>{{Cite news |url=https://www.livescience.com/27405-manatees.html |title=Manatees: Facts About Sea Cows |work=Live Science |access-date=17 June 2018 |archive-url=https://web.archive.org/web/20180617115739/https://www.livescience.com/27405-manatees.html |archive-date=17 June 2018 |url-status=live}}</ref>

The Amazon and its tributaries are the main habitat of the [[giant otter]] (''Pteronura brasiliensis'').<ref>{{Cite book |url=https://books.google.com/books?id=z0zfBQAAQBAJ&q=The+Amazon+and+its+tributaries+are+the+main+habitat+of+the+giant+otter+(Pteronura+brasiliensis).&pg=PA36 |title=Forests |last=Balliett |first=James Fargo |year=2014 |publisher=Routledge |isbn=978-1-317-47033-5 |language=en |access-date=15 October 2020 |archive-date=2 November 2023 |archive-url=https://web.archive.org/web/20231102052634/https://books.google.com/books?id=z0zfBQAAQBAJ&q=The+Amazon+and+its+tributaries+are+the+main+habitat+of+the+giant+otter+%28Pteronura+brasiliensis%29.&pg=PA36#v=onepage&q=The%20Amazon%20and%20its%20tributaries%20are%20the%20main%20habitat%20of%20the%20giant%20otter%20(Pteronura%20brasiliensis).&f=false |url-status=live }}</ref> Sometimes known as the "river wolf," it is one of South America's top carnivores. Because of habitat destruction and hunting, its population has dramatically decreased. It is now listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), which effectively bans international trade.<ref>{{Cite web |url=http://www.arkive.org/giant-otter/pteronura-brasiliensis/ |title=Giant otter videos, photos and facts – Pteronura brasiliensis |website=Arkive |language=en-GB |access-date=2 February 2018 |archive-url=https://web.archive.org/web/20180107031811/http://www.arkive.org/giant-otter/pteronura-brasiliensis/ |archive-date=7 January 2018 }}</ref>

==== Reptiles ====
[[File:Anaconda (Eunectes murinus) (8990193853).jpg|thumb|The [[green anaconda]] is the [[List of largest snakes|heaviest and one of the longest]] known extant snake species.]]

The [[anaconda]] is found in shallow waters in the Amazon basin. One of the world's largest species of snake, the anaconda spends most of its time in the water with just its nostrils above the surface. Species of [[caiman]]s, that are related to alligators and other crocodilians, also inhabit the Amazon as do varieties of turtles.<ref name=AnimalDiversity>[http://animaldiversity.org/accounts/Paleosuchus_palpebrosus/ Cuvier's smooth-fronted caiman (''Paleosuchus palpebrosus'')] {{webarchive |url=https://web.archive.org/web/20171023064202/http://animaldiversity.org/accounts/Paleosuchus_palpebrosus/ |date=23 October 2017 }}</ref>

==== Birds ====
{{category see also|Birds of the Amazon rainforest}}

==== Fish ====
[[File:Piranha1.jpg|thumb|[[Characin]]s, such as the [[piranha]] species, are prey for the [[giant otter]], but these aggressive fish may also pose a danger to humans.]]
[[File:Neon tetra 333.jpg|thumb|The [[neon tetra]] is one of the most popular aquarium fish.]]

The Amazonian fish fauna is the centre of diversity for [[neotropical fishes]], some of which are popular aquarium specimens like the [[Neon Tetra|neon tetra]] and the [[Freshwater Angelfish|freshwater angelfish]]. More than 5,600 species were known {{as of|2011|lc=y}}, and approximately fifty new species are discovered each year.<ref name=Albert;Reis/>{{rp|308}}<ref name=Wohl/>{{rp|27}} The [[arapaima]], known in Brazil as the ''pirarucu'', is a South American tropical [[freshwater fish]], one of the largest freshwater fish in the world, with a length of up to {{convert|15|ft|m|order=flip}}.<ref>[http://news.nationalgeographic.com/news/2007/07/070724-giant-fish.html Megafishes Project to Size Up Real "Loch Ness Monsters"] {{webarchive |url=https://web.archive.org/web/20090903123613/http://news.nationalgeographic.com/news/2007/07/070724-giant-fish.html |date=3 September 2009 }}. ''National Geographic''.</ref> Another Amazonian freshwater fish is the [[arowana]] (or ''aruanã'' in Portuguese), such as the [[silver arowana]] (''[[Osteoglossum bicirrhosum]]''), which is a predator and very similar to the arapaima, but only reaches a length of {{cvt|120|cm|sp=us}}. Also present in large numbers is the notorious [[piranha]], an omnivorous fish that congregates in large schools and may attack livestock. There are approximately 30 to 60 species of piranha. The [[candirú]], native to the Amazon River, is a species of parasitic fresh water [[catfish]] in the family [[Trichomycteridae]],<ref>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/92428/candiru |title=Candiru (fish) |encyclopedia=[[Encyclopædia Britannica Online]] |access-date=18 July 2014 |url-status=live |archive-url=https://web.archive.org/web/20140718090841/https://www.britannica.com/EBchecked/topic/92428/candiru |archive-date=18 July 2014}}</ref> just one of more than 1200 species of catfish in the Amazon basin. Other catfish 'walk' overland on their ventral fins,<ref name=Wohl/>{{rp|27&ndash;29}} while the [[kumakuma]] (''Brachyplatystoma filamentosum''), aka ''piraiba'' or "goliath catfish", can reach {{cvt|3.6|m|ft|sp=us}} in length and {{cvt|200|kg|sp=us}} in weight.<ref>{{cite book |url=https://books.google.com/books?id=eGGqGYEQXDkC&pg=PA31 |title=Fish Conservation: A Guide to Understanding and Restoring Global Aquatic Biodiversity and Fishery Resources |first=Gene S. |last=Helfman |page=31 |publisher=Island Press |year=2007 |access-date=28 March 2016 |isbn=978-1-59726-760-1 |url-status=live |archive-url=https://web.archive.org/web/20170208041731/https://books.google.com/books?id=eGGqGYEQXDkC&pg=PA31 |archive-date=8 February 2017}}</ref>

The [[electric eel]] (''Electrophorus electricus'') and more than 100 species of electric fishes ([[Gymnotiformes]]) inhabit the Amazon basin. River stingrays ([[Potamotrygonidae]]) are also known. The [[bull shark]] (''Carcharhinus leucas''), a [[euryhaline]] species which can thrive in both salt and fresh water, has been reported as far as {{cvt|4000|km|sp=us}} up the Amazon River at [[Iquitos]] in Peru.<ref>{{Cite web |url=http://www.loyno.edu/lucec/natural-history-writings/bull-sharks-carcharhinus-leucus-coastal-estuaries |title=Bull Sharks, Carcharhinus leucus, In Coastal Estuaries {{!}} Center for Environmental Communication {{!}} Loyola University New Orleans |website=www.loyno.edu |access-date=2019-09-12 |archive-url=https://web.archive.org/web/20190804011530/http://www.loyno.edu/lucec/natural-history-writings/bull-sharks-carcharhinus-leucus-coastal-estuaries |archive-date=4 August 2019 |url-status=live}}</ref>

==== Butterflies ====
{{see also|List of butterflies of the Amazon River basin and the Andes}}

==== Microbiota ====
Freshwater [[Microorganism|microbes]] are generally not very well known, even less so for a pristine [[ecosystem]] like the Amazon. Recently, [[metagenomics]] has provided answers to what kind of [[Microorganism|microbes]] inhabit the river.<ref name="amazonMetagenome">{{cite journal |vauthors=Ghai R, Rodriguez-Valera F, McMahon KD |title=Metagenomics of the water column in the pristine upper course of the Amazon river |journal=PLOS ONE |volume=6 |issue=8 |pages=e23785 |year=2011 |doi=10.1371/journal.pone.0023785 |pmid=21915244 |pmc=3158796 |bibcode=2011PLoSO...623785G |display-authors=etal |doi-access=free}}</ref> The most important [[Microorganism|microbes]] in the Amazon River are [[Actinomycetota]], [[Alphaproteobacteria]], [[Betaproteobacteria]], [[Gammaproteobacteria]] and [[Thermoproteota]].

== Challenges ==
The Amazon River serves as a vital lifeline for more than 47 million people in its basin and faces a multitude of challenges that threaten both its ecosystem and the indigenous communities dependent on its resources. According to the Office of the [[Office of the United Nations High Commissioner for Human Rights|United Nations High Commissioner for Human Rights]] (OHCHR), the [[Yanomami]], a tribe of approximately 29,000, struggles to preserve their land, culture, and traditional way of life due to encroaching illegal gold miners, [[malnutrition]], and malaria. Meanwhile, in 2022, the region's severe [[drought]], has led to a devastating increase in water temperatures, reaching 39.1 degrees Celsius, causing the demise of 125 Amazon river dolphins.<ref>{{cite web |title=In the Amazon rainforest, an indigenous tribe fights for survival |url=https://www.ohchr.org/en/stories/2022/08/amazon-rainforest-indigenous-tribe-fights-survival |access-date=9 August 2022 |website=United Nation}}</ref> This event displays the deteriorating environmental conditions and indicates the increasing vulnerability of the river's ecosystem. In recent years, the Amazon River has experienced historically low water levels, the lowest in over a century. Brazil, the primary custodian of this invaluable natural resource, grapples with the challenges of mitigating the effects of this drought on communities and ecosystems, further emphasizing the urgency of sustainable environmental management and conservation efforts.<ref>{{Cite web |title=Amazon River falls to lowest in over 100 years as Brazil struggles with drought |url=https://www.indiatoday.in/environment/story/amazon-river-falls-to-lowest-in-over-100-years-as-brazil-struggles-with-drought-2450012-2023-10-17 |access-date=2023-11-07 |website=India Today |date=17 October 2023 |language=en}}</ref>

== Major tributaries ==
[[File:Aerial view of the Amazon Rainforest.jpg|thumb|[[Solimões]], the section of the upper Amazon River]]
[[File:Amazonie jt01.png|thumb|Aerial view of an Amazon tributary]]

The Amazon has over 1,100 [[Tributary|tributaries]], twelve of which are over {{cvt|1500|km|sp=us}} long.<ref>Tom Sterling: ''Der Amazonas''. Time-Life Bücher 1979, 8th German Printing, p. 20.</ref> Some of the more notable ones are:

{{Div col|colwidth=15em}}
* [[Branco River|Branco]]
* [[Casiquiare canal]]
* [[Caqueta River|Caquetá]]
* [[Huallaga River|Huallaga]]
* [[Putumayo River|Putumayo (or Içá River)]]
* [[Javary River|Javary (or Yavarí)]]
* [[Juruá River|Juruá]]
* [[Madeira River|Madeira]]
* [[Marañón River|Marañón]]
* [[Morona]]
* [[Nanay River|Nanay]]
* [[Napo River|Napo]]
* [[Rio Negro (Amazon)|Negro]]
* [[Pastaza River|Pastaza]]
* [[Purús River|Purús]]
* [[Tambo River (Peru)|Tambo]]
* [[Tapajós]]
* [[Tigre River|Tigre]]
* [[Tocantins River|Tocantins]]
* [[Trombetas]]
* [[Ucayali River|Ucayali]]
* [[Xingu River|Xingu]]
* [[Japurá River|Yapura]]
{{colend}}

=== List of major tributaries ===
The main river and tributaries are (sorted in order from the confluence of Ucayali and Marañón rivers to the mouth):
{| class="wikitable" style="text-align:center;"
 ! Left tributary
 ! Right tributary
 ! Length (km)
 ! Basin size (km<sup>2</sup>)
 ! Average discharge (m<sup>3</sup>/s)
 |-
| colspan="5" |'''Upper Amazon'''
(Confluence of Ucayali and Marañón rivers ''-'' [[Tabatinga]])
 |-
 |[[Marañón River|Marañón]]
 |
 |2,112
 |364,873.4
 |16,708
 |-
 | rowspan="3" |
 |[[Ucayali River|Ucayali]]
 |2,738
 |353,729.3
 |13,630.1
 |-
|Tahuyo
 
|80
 |1,630
 |105.7
 |-
|Tamshiyaçu
 
|86.7
 |1,367.3
 |86.5
 |-
 |[[Itaya River|Itaya]]
 | rowspan="2" |
 |213
 |2,668
 |161.4
 |-
 |[[Nanay River|Nanay]]
 
|483
 
|16,673.4
 |1,072.7
 |-
 |
 |Maniti
 |198.7
 |2,573.6
 |180.4
 |-
 |[[Napo River|Napo]]
 | rowspan="2" |
 |1,075
 |103,307.8
 |7,147.8
 |-
 |Apayaçu
 
|50
 
|2,393.6
 |160.9
 |-
 |
 |Orosa
 |95
 |3,506.8
 |234.3
 |-
 |Ampiyaçu
 | rowspan="2" |
 |140
 |4,201.4
 |267.2
 |-
 |Chichita
 
|48
 
|1,314.2
 |87.7
 |-
 | rowspan="2" |
 |Cochiquinas
 |49
 |2,362.7
 |150.2
 |-
|Santa Rosa
 
|45
 |1,678
 |101.5
 |-
 |Cajocumal
 | rowspan="2" |
 |58
 |2,094.9
 |141.5
 |-
 |Atacuari
 
|108
 
|3,480.5
 |236.8
 |-
| colspan="5" |'''[[Solimões River|Middle Amazon]]'''
([[Tabatinga]] ''-'' [[Meeting of Waters|Encontro das Águas]])
 |-
 | rowspan="2" |
 |[[Javary River|Javary]]
 |1,056
 |99,674.1
 |5,222.5
 |-
|Igarapé 
Veneza
 
|
 |943.9
 |58.3
 |-
 |Tacana
 | rowspan="3" |
 |
 |541
 |35.5
 |-
 |Igarapé de 
Belém
 
|
 
|1,299.9
 |85.4
 |-
 |Igarapé São 
Jerônimo
 
|
 
|1,259.6
 |78.2
 |-
 | rowspan="2" |
 |[[Jandiatuba River|Jandiatuba]]
 |520
 |14,890.4
 |980
 |-
|Igarapé 
Acuruy
 
|
 |2,462.1
 |127.1
 |-
 |[[Putumayo River|Putumayo]]
 | rowspan="2" |
 |1,813
 |121,115.8
 |8,519.9
 |-
 |[[Tonantins River|Tonantins]]
 
|
 
|2,955.2
 |169.2
 |-
 | rowspan="3" |
 |[[Jutaí River|Jutai]]
 |1,488
 |78,451.5
 |4,000
 |-
|[[Juruá River|Juruá]]
 
|3,283
 |190,573
 |6,662.1
 |-
|[[Uarini River|Uarini]]
 
|
 |7,195.8
 |432.9
 |-
 |[[Japurá River|Japurá]]
 |
 |2,816
 |276,812
 |18,121.6
 |-
 | rowspan="2" |
 |[[Tefé River|Tefé]]
 |571
 |24,375.5
 |1,190.4
 |-
|Caiambe
 
|
 |2,650.1
 |90
 |-
 |Parana Copea
 |
 |
 |10,532.3
 |423.8
 |-
 | rowspan="2" |
 |[[Coari River|Coari]]
 |599
 |35,741.3
 |1,389.3
 |-
|[[Mamiá River (Amazonas)|Mamiá]]
 
|
 |5,514
 |176.2
 |-
 |[[Piorini River|Badajos]]
 | rowspan="2" |
 |413
 |21,575
 |1,300
 |-
 |Igarapé Miuá
 
|
 
|1,294.5
 |56.9
 |-
 |
 |[[Purus River|Purus]]
 |3,382
 |378,762.4
 |11,206.9
 |-
 |Paraná Arara
 |
 |
 |1,915.7
 |78.2
 |-
 |
 |Paraná 
Manaquiri
 |
 |1,318.6
 |52.9
 |-
 |[[Manacapuru River|Manacapuru]]
 |
 |291
 |14,103
 |559.5
 |-
| colspan="5" |'''Lower Amazon'''
([[Meeting of Waters|Encontro das Águas]] ''-'' [[Gurupá]])
 |-
 |[[Negro River (Amazon)|Rio Negro]]
 | rowspan="2" |
 |2,362
 |714,577.6
 |30,640.8
 |-
 |[[Rio Preto da Eva|Prêto da Eva]]
 
|
 
|3,039.5
 |110.8
 |-
 | rowspan="2" |
 |[[Igapó-Açu River|Igapó-Açu]]
 |500
 |45,994.4
 |1,676.5
 |-
|[[Madeira River|Madeira]]
 
|3,380
 |1,322,782.4
 |32,531.9
 |-
 |[[Urubu River (Amazonas)|Urubu]]
 | rowspan="2" |
 |430
 |13,892
 |459.8
 |-
 |[[Uatumã River|Uatumã]]
 
|701
 
|67,920
 |2,290.8
 |-
 |
 |[[Canumã River|Canumã]],
[[Paraná do Urariá]]
 |400
 |127,116
 |4,804.4
 |-
 |[[Nhamundá River|Nhamundá]],
[[Trombetas River|Trombetas]]
 | rowspan="2" |
 |744
 |150,032
 |4,127
 |-
 |[[Curuá River (Amazon River tributary)|Curuá]]
 
|484
 
|28,099
 |470.1
 |-
 | rowspan="3" |
 |Lago Grande 
do Curuaí
 |
 |3,293.6
 |92.7
 |-
|[[Tapajós River|Tapajós]]
 
|1,992
 |494,551.3
 |13,540
 |-
|[[Curuá Una River|Curuá-Una]]
 
|315
 |24,505
 |729.8
 |-
 |[[Maicuru River|Maicurú]]
 |
 |546
 |18,546
 |272.3
 |-
 |
 |Uruará
 |
 |4,610.2
 |104.8
 |-
 |[[Jauaru River|Jauari]]
 |
 |
 |5,851
 |108.3
 |-
 |
 |[[Guajará River (Amazon)|Guajará]]
 |
 |4,243
 |105.6
 |-
 |[[Paru River|Paru de Este]]
 |
 |731
 |39,289
 |970
 |-
 |
 |[[Xingu River|Xingu]]
 |2,275
 |513,313.5
 |10,022.6
 |-
 |Igarapé 
Arumanduba
 | rowspan="2" |
 |
 |1,819.9
 |50.8
 |-
 |[[Jari River|Jari]]
 
|769
 
|51,893
 |1,213.5
 |-
| colspan="5" |'''[[Amazon Delta]]'''
(river mouth to [[Gurupá]])
 |-
 |Braco do 
Cajari
 |
 |
 |4,732.4
 |157.1
 |-
 | rowspan="2" |
 |[[Pará River|Pará]]
 |784
 |84,027
 |3,500.3
 |-
|[[Tocantins River|Tocantins]]
 
|2,639
 |777,308
 |11,796
 |-
 |[[Atuá River|Atuã]]
 |
 |
 |2,769
 |119.8
 |-
 |
 |[[Anajás River|Anajás]]
 |300
 |24,082.5
 |948
 |-
 |Mazagão
 | rowspan="3" |
 |
 |1,250.2
 |44.4
 |-
 |[[Vila Nova River|Vila Nova]]
 
|
 
|5,383.8
 |180.8
 |-
 |[[Matapi River|Matapi]]
 
|
 
|2,487.4
 |81.7
 |-
 |
 |[[Acará River|Acará]],
[[Guamá River|Guamá]]
 |400
 |87,389.5
 |2,550.7
 |-
 |[[Arari River|Arari]]
 | rowspan="2" |
 |
 |1,523.6
 |80.2
 |-
 |[[Pedreira River|Pedreira]]
 
|
 
|2,005
 |89.9
 |-
 |
 |[[Paracauari River|Paracauari]]
 |
 |1,390.3
 |67.9
 |-
 |[[Jupati River|Jupati]]
 |
 |
 |724.2
 |32.6
|}
<ref>{{cite web |url=https://www.amazonwaters.org/ |title=Aguas Amazonicas |access-date=31 October 2022 |archive-date=11 November 2022 |archive-url=https://web.archive.org/web/20221111184115/https://amazonwaters.org/ |url-status=live }}</ref><ref>{{cite web |url=https://www.ore-hybam.org/ |title=HyBam |access-date=31 October 2022 |archive-date=29 August 2020 |archive-url=https://web.archive.org/web/20200829163121/https://www.ore-hybam.org/ |url-status=live }}</ref><ref name="Rivers Network">{{cite web |url=https://www.riversnetwork.org/ |title=Rivers Network |access-date=27 March 2022 |archive-date=16 March 2022 |archive-url=https://web.archive.org/web/20220316161153/https://www.riversnetwork.org/ |url-status=live }}</ref><ref>{{cite web |url=https://www.meioambiente.am.gov.br/ |title=Secretaría do Meio Ambiente (SEMA) |access-date=31 October 2022 |archive-date=6 November 2022 |archive-url=https://web.archive.org/web/20221106213601/https://meioambiente.am.gov.br/ |url-status=live }}</ref><ref>{{cite web |url=https://www.gov.br/ |title=Agência Nacional de Águas e Saneamento Básico (ANA) |access-date=31 October 2022 |archive-date=11 February 2021 |archive-url=https://web.archive.org/web/20210211163720/https://www.gov.br/ |url-status=live }}</ref><ref name="Lower Amazon"/>

=== List by length ===
# {{cvt|6400|km|sp=us}}<ref name=britannica-amazon /> ({{cvt|6275|to|7025|km|mi}})<ref name=liu-etal-river-length/> – Amazon, South America
# {{cvt|3250.|km|sp=us}} – [[Madeira River|Madeira]], Bolivia/Brazil<ref>{{cite web |url=http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0023864.html |title=Madeira (river) |publisher=Talktalk.co.uk |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20121003091951/http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0023864.html |archive-date=3 October 2012}}</ref>
# {{cvt|3211|km|sp=us}} – [[Purús River|Purús]], Peru/Brazil<ref>{{cite web |url=http://www.answers.com/topic/purus-river-geoglam-in-encyclopedia |title=Purus River: Information from |publisher=Answers.com |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20110628181628/http://www.answers.com/topic/purus-river-geoglam-in-encyclopedia |archive-date=28 June 2011}}</ref>
# {{cvt|2820.|km|sp=us}} – [[Japurá River|Japurá or Caquetá]], Colombia/Brazil<ref>{{cite web |url=https://www.britannica.com/EBchecked/topic/301337/Japura-River |last=McKenna |first=Amy |title=Japurá River (river, South America) |website=Encyclopædia Britannica |date=9 February 2007 |access-date=16 July 2017 |url-status=live |archive-url=https://web.archive.org/web/20150503140232/https://www.britannica.com/EBchecked/topic/301337/Japura-River |archive-date=3 May 2015}}</ref>
# {{cvt|2639|km|mi}} – [[Tocantins River|Tocantins]], Brazil<ref>{{cite web |url=http://www.infoplease.com/encyclopedia/places/latin-america-and-the-caribbean/latin-american-and-caribbean-physical-geography/tocantins-river-brazil |last=Infoplease |title=Tocantins |date=2012 |access-date=2 August 2017 |url-status=live |archive-url=https://web.archive.org/web/20170803085428/https://www.infoplease.com/encyclopedia/places/latin-america-and-the-caribbean/latin-american-and-caribbean-physical-geography/tocantins-river-brazil |archive-date=3 August 2017}}</ref>
# {{cvt|2627|km|mi}} – [[Araguaia River|Araguaia]], Brazil (tributary of Tocantins)<ref>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/31943/Araguaia-River |title=Araguaia River (river, Brazil) – Encyclopædia Britannica |encyclopedia=Encyclopædia Britannica |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20110629065524/https://www.britannica.com/EBchecked/topic/31943/Araguaia-River |archive-date=29 June 2011}}</ref>
# {{cvt|2400|km||sp=us}} – [[Juruá River|Juruá]], Peru/Brazil<ref>{{cite web |url=http://www.answers.com/topic/ju-ru-river |title=Juruá River: Information from |publisher=Answers.com |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20110628181633/http://www.answers.com/topic/ju-ru-river |archive-date=28 June 2011}}</ref>
# {{cvt|2250|km|sp=us}} – [[Rio Negro (Amazon)|Rio Negro]], Brazil/Venezuela/Colombia<ref>{{cite web |url=http://www.answers.com/topic/negro-river-chaco |title=Negro River: Information from |publisher=Answers.com |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20110628181649/http://www.answers.com/topic/negro-river-chaco |archive-date=28 June 2011}}</ref>
# {{cvt|1992|km|mi}} – [[Tapajós]], Brazil<ref>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/583075/Tapajos-River |title=Tapajos River (river, Brazil) – Encyclopædia Britannica |encyclopedia=Encyclopædia Britannica |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20110111023217/https://www.britannica.com/EBchecked/topic/583075/Tapajos-River |archive-date=11 January 2011}}</ref>
# {{cvt|1979|km|mi}} – [[Xingu River|Xingu]], Brazil<ref>{{cite web |url=http://www.internationalrivers.org/en/xingu |title=Xingu River |publisher=International Rivers |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20101227170145/http://www.internationalrivers.org/en/xingu |archive-date=27 December 2010}}</ref>
# {{cvt|1900.|km|mi}} – [[Ucayali River]], Peru<ref>{{cite web |url=http://geography.howstuffworks.com/south-america/the-ucayali-river.htm |title=HowStuffWorks "The Ucayali River" |publisher=Geography.howstuffworks.com |date=30 March 2008 |access-date=13 February 2011 |archive-url=https://web.archive.org/web/20120401063627/http://geography.howstuffworks.com/south-america/the-ucayali-river.htm |archive-date=1 April 2012}}</ref>
# {{cvt|1749|km|mi}} – [[Guaporé River|Guaporé]], Brazil/Bolivia (tributary of Madeira)<ref>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/247824/Guapore-River |title=Guapore River (river, South America) – Encyclopædia Britannica |encyclopedia=Encyclopædia Britannica |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20110629065716/https://www.britannica.com/EBchecked/topic/247824/Guapore-River |archive-date=29 June 2011}}</ref>
# {{cvt|1575|km|mi}} – [[Putumayo River|Içá (Putumayo)]], Ecuador/Colombia/Peru
# {{cvt|1415|km|mi}} – [[Marañón River|Marañón]], Peru
# {{cvt|1370.|km|mi}} – [[Teles Pires]], Brazil (tributary of Tapajós)
# {{cvt|1300.|km|mi}} – [[Iriri River|Iriri]], Brazil (tributary of Xingu)
# {{cvt|1240.|km|mi}} – [[Juruena River|Juruena]], Brazil (tributary of Tapajós)
# {{cvt|1130.|km|mi}} – [[Madre de Dios River|Madre de Dios]], Peru/Bolivia (tributary of Madeira)
# {{cvt|1100.|km|mi}} – [[Huallaga River|Huallaga]], Peru (tributary of Marañón)

=== List by inflow to the Amazon ===
{| class="wikitable"
|-
! Rank !! Name !! Average annual discharge (m^3/s) !! % of Amazon
|-
| || Amazon || 209,000 || 100% 
|-
| 1 || Madeira || 31,200 || 15%
|-
| 2 || Negro || 28,400 || 14%
|-
| 3 || Japurá || 18,620 || 9%
|-
| 4 || Marañón || 16,708 || 8%
|-
| 5 || Tapajós || 13,540 || 6%
|-
| 6 || Ucayali || 13,500 || 5%
|-
| 7 || Purus || 10,970 || 5%
|-
| 8 || Xingu || 9,680 || 5%
|-
| 9 || Putumayo || 8,760 || 4%
|-
| 10 || Juruá || 8,440 || 4%
|-
| 11 || Napo || 6,976 || 3%
|-
| 12 || Javari || 4,545 || 2%
|-
| 13 || Trombetas || 3,437 || 2%
|-
| 14 || Jutaí || 3,425 || 2%
|-
| 15 || Abacaxis || 2,930 || 2%
|-
| 16 || Uatumã || 2,190 || 1%
|}

== See also ==
{{portal|Geography|Brazil|Colombia|Peru}}
* [[Amazon natural region]], in Colombia
* [[Peruvian Amazonia]] in Peru
* [[Nile]]

{{Clear}}

==Notes==

{{reflist|group=n}}

== References ==
{{Reflist}}

=== Bibliography ===
** {{EB1911 |last=Church |first=George Earl |author-link=George Earl Church |wstitle=Amazon |volume=1 |pages=783–90}}
* Garfield, Seth. ''In search of the Amazon: Brazil, the United States and the nature of a region'' (Duke University Press, 2013) [https://library.oapen.org/bitstream/handle/20.500.12657/30139/1/649961.pdf online]
* Hecht, Susanna, et al. "The Amazon in motion: Changing politics, development strategies, peoples, landscapes, and livelihoods." ''Amazon Assessment Report 2021, Part II'' (2021): ch 14 pp 1–65. [https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/526184/3/Chapter14-Amazon-Assessment-Report-2021-Part-II-reduced.pdf online, with long bibliography]
* Nugent, Stephen L. ''The rise and fall of the Amazon rubber industry: an historical anthropology'' (Routledge, 2017) [https://books.google.com/books?id=ZiBBDwAAQBAJ&dq=Amazon&pg=PT6 online].
* Schulze, Frederik, and Georg Fischer. "Brazilian history as global history." ''Bulletin of Latin American Research'' 38.4 (2019): 408–422. [https://onlinelibrary.wiley.com/doi/abs/10.1111/blar.12781 online]
* {{cite book |last=Wohl |first=Ellen |year=2011 |title=The Amazon: Rivers of Blushing Dolphins |series=A World of Rivers |publisher=The [[University of Chicago]] Press}}

== External links ==
{{Sister project links
|1=Amazon River |collapsible=yes |display=Amazon river |author= |commonscat=yes |b=no |c=Amazon river |d=Q3783 |m=no |mw=no |n=no |q=no |s=The New International Encyclopædia/Amazon |species=no |species_author=no |v=no |voy=Voyaging along the Amazon River |wikt=no
}}
* [https://web.archive.org/web/20100206042928/http://www.extremescience.com/AmazonRiver.htm Information on the Amazon from Extreme Science]
* [http://jordibusque.com/en/story/amazonas/CF0646-DSC_5912.jpg#/CF0646-DSC_5912.jpg A photographic journey up the Amazon River from its mouth to its source]
* [https://web.archive.org/web/20170826071647/http://www.lightandshadow.tv/index.php?option=com_content&view=article&id=57&Itemid=113&lang=en Amazon Alive: Light & Shadow documentary film about the Amazon river]
* [http://www.discover-peru.org/peru-geography-amazon-river-ecosystem/ Amazon River Ecosystem]
* [http://dornsife.usc.edu/labs/capone/anacondas Research on the influence of the Amazon River on the Atlantic Ocean at the University of Southern California] {{Webarchive|url=https://web.archive.org/web/20191109011024/https://dornsife.usc.edu/labs/capone/anacondas/ |date=9 November 2019 }}
* {{osmrelation-inline|2295651}}

{{Treasures of Colombia}}
{{New7Wonders of Nature|state=expanded}}

{{Authority control}}

[[Category:Amazon River| ]]
[[Category:Amazon basin]]
[[Category:Amazon rainforest]]
[[Category:Upper Amazon]]
[[Category:Rivers of South America]]
[[Category:International rivers of South America]]
[[Category:Rivers of Colombia]]
[[Category:Rivers of Peru]]
[[Category:Colombia–Peru border]]
[[Category:Rivers of Amapá]]
[[Category:Rivers of Amazonas (Brazilian state)]]
[[Category:Rivers of the Department of Loreto]]
[[Category:Rivers of Pará]]