Editing Geography of the United States (section)

==Physiographic divisions==
[[File:US physiographic map.jpg|thumb|A [[physiography|physiographical]] map of the contiguous 48 states of the U.S. and indicating the age of the exposed surface and the type of terrain]]
[[File:Scipio Township near Republic.jpg|thumb|An aerial photo over northern [[Ohio]]; much of the central United States is covered by relatively flat, arable land.]]
Within the continental U.S. there are  [[Physiographic regions of the United States|eight distinct physiographic divisions]].<ref>{{cite web|title=Physiographic Regions |publisher=[[United States Geological Survey]] |date=2003-04-17 |url=http://tapestry.usgs.gov/physiogr/physio.html |access-date=2008-01-30 |url-status=dead |archive-url=https://web.archive.org/web/20060515044037/http://tapestry.usgs.gov/physiogr/physio.html |archive-date=2006-05-15 }}</ref> These major divisions are:

* [[Laurentian Upland]] – part of the [[Canadian Shield]] that extends into the northern United States [[Great Lakes (North America)|Great Lakes]] area.
* [[Atlantic Plain]] – the coastal regions of the eastern and southern parts include the continental shelf, the [[East Coast of the United States|Atlantic Coast]] and the [[U.S. Gulf Coast|Gulf Coast]].
* [[Appalachian Highlands]] – lying on the eastern side of the United States, it includes the [[Appalachian Mountains]], the [[Watchung Mountains]], the [[Adirondacks]] and [[New England]] province originally containing the Great Eastern Forest, a stretch of mixed temperature and subtropical montane forests, some of which are rainforests.
* [[Interior Plains]] – part of the interior continental United States, it includes the [[Great Plains]], as well as a number of highland and mountainous regions, like the [[Black Hills]], dense cave systems, painted hills and badland features.
* [[Interior Highlands]] – also part of the interior continental United States, this division includes the [[Ozark]] Plateau, the [[Ouachita Mountains]], and other smaller mountain systems. This region is located largely in the warm temperate/subtropical moist and dry forest biomes.
* [[Rocky Mountains|Rocky Mountain System]] – one branch of the [[American Cordillera]] system lying far inland in the western states.
* [[Geography of the United States Intermontane Plateaus|Intermontane Plateaus]] – also divided into the [[Columbia Plateau]], the [[Colorado Plateau]] and the [[Basin and Range Province]], it is a system of plateaus, basins, ranges and gorges between the Rocky and Pacific Mountain Systems. It is the setting for the [[Grand Canyon]], the [[Great Basin]] and [[Death Valley]].
* [[Pacific Coast Ranges|Pacific Mountain System]] – the coastal mountain ranges and features in the [[West Coast of the United States|west coast of the United States]].
[[File:MountMcKinley BA.jpg|thumb|[[Denali]], federally designated as Mount McKinley, in [[Alaska]], is the tallest mountain in North America, at {{convert|20310|ft|m|1|abbr=on}}.]]
[[File:Grand Canyon from Moran Point.jpeg|thumb|[[The Grand Canyon]], seen here from Moran Point, is among the most visited locations in the country.]]

The [[eastern United States]] has a varied topography. A broad, flat coastal plain lines the Atlantic and Gulf shores from the Texas-Mexico border to [[New York City]], and includes the Florida peninsula. This broad coastal plain and [[barrier islands]] make up the widest and longest beaches in the United States, much of it composed of soft, white sands. The [[Florida Keys]] are a string of [[Coral island|coral islands]] that reach the southernmost city on the United States mainland at [[Key West]] in [[South Florida]].

Areas further inland feature rolling hills, mountains, and a diverse collection of temperate and subtropical moist and wet forests. Parts of interior Florida and South Carolina are also home to [[sandhill]] communities. The [[Appalachian Mountains]] form a line of low mountains separating the eastern seaboard from the [[Great Lakes Basin|Great Lakes]] and the [[Mississippi River|Mississippi basins]]. [[New England]] features rocky seacoasts and rugged mountains with peaks up to 6,200 feet and valleys dotted with rivers and streams. Offshore islands dot the Atlantic and Gulf coasts. A recent global remote sensing analysis suggested that there were 6,622&nbsp;km² of [[Mudflat|tidal flats]] in the United States, making it the 4th ranked country in terms of tidal flat area.<ref>{{cite journal |last1=Murray |first1=N.J. |last2=Phinn |first2=S.R. |last3=DeWitt |first3=M. |last4=Ferrari |first4=R. |last5=Johnston |first5=R. |last6=Lyons |first6=M.B. |last7=Clinton |first7=N. |last8=Thau |first8=D. |last9=Fuller |first9=R.A. |title=The global distribution and trajectory of tidal flats |journal=Nature |date=2019 |volume=565 |issue=7738 |pages=222–225 |doi=10.1038/s41586-018-0805-8 |pmid=30568300 |s2cid=56481043 |url=https://www.nature.com/articles/s41586-018-0805-8}}</ref>

The five [[Great Lakes]] are located in the north-central portion of the country, four of them forming part of the border with Canada; only [[Lake Michigan]] is situated entirely within the United States. The [[Southeastern United States|southeast United States]], generally stretching from the [[Ohio River]] southwards, includes a variety of warm temperate and subtropical moist and wet forests, as well as warm temperate and subtropical dry forests nearer the [[Great Plains]] in the west of the region. West of the Appalachians lies the lush Mississippi River basin and two large eastern tributaries, the Ohio River and the [[Tennessee River]]. The Ohio and [[Tennessee Valley|Tennessee]] valleys and the [[Midwestern United States|Midwest]] consist largely of rolling hills, interior highlands and small mountains, jungle-like marsh and swampland near the Ohio River, and productive farmland, stretching south to the [[Gulf Coast of the United States|Gulf Coast]]. The Midwest also has a vast amount of cave systems.

The Great Plains lie west of the Mississippi River and east of the [[Rocky Mountains]]. A large portion of the country's agricultural products are grown in the Great Plains. Before their general conversion to farmland, the Great Plains were noted for their extensive grasslands, from [[tallgrass prairie]] in the eastern plains to [[shortgrass prairie|shortgrass steppe]] in the western [[High Plains (United States)|High Plains]]. Elevation rises gradually from less than a few hundred feet near the Mississippi River to more than a mile high in the High Plains. The generally low relief of the plains is broken in several places, most notably in the [[The Ozarks|Ozark]] and [[Ouachita Mountains]], which form the [[U.S. Interior Highlands]], the only major mountainous region between the Rocky Mountains and the Appalachian Mountains.<ref>{{cite web | url=http://www.srs.fs.usda.gov/4106/about/HotSpringsOffice.htm | title=Managing Upland Forests of the Midsouth | publisher=United States Forestry Service | access-date=2007-10-13 | url-status=dead | archive-url=https://web.archive.org/web/20071017222856/http://srs.fs.usda.gov/4106/about/HotSpringsOffice.htm | archive-date=2007-10-17 }}</ref><ref>{{cite web|url=http://tapestry.usgs.gov/physiogr/physio.html |title=A Tapestry of Time and Terrain: The Union of Two Maps – Geology and Topography |publisher=United States Geological Survey |access-date=2007-10-13 |url-status=dead |archive-url=https://web.archive.org/web/20060515044037/http://tapestry.usgs.gov/physiogr/physio.html |archive-date=2006-05-15 }}</ref>

The Great Plains come to an abrupt end at the Rocky Mountains. The Rocky Mountains form a large portion of the [[Western U.S.]], entering from Canada and stretching nearly to Mexico. The Rocky Mountain region is the highest region of the United States by average elevation. The Rocky Mountains generally contain fairly mild slopes and wider peaks compared to some of the other great mountain ranges, with a few exceptions, including the [[Teton Range]] in [[Wyoming]] and the [[Sawatch Range]] in [[Colorado]]. The highest peaks of the Rockies are found in Colorado, the tallest peak being [[Mount Elbert]] at {{convert|14440|ft|m|abbr=on}}. Instead of being one generally continuous and solid mountain range, it is broken up into several smaller intermittent mountain ranges, forming a large series of basins and valleys.

West of the Rocky Mountains lies the [[Intermontane Plateaus]], also known as the [[Intermountain West]], a large, arid desert lying between the Rockies and the [[Cascade Range|Cascades]] and [[Sierra Nevada]] ranges. The large southern portion, known as the [[Great Basin]], consists of salt flats, drainage basins, and many small north–south mountain ranges. The [[Southwestern United States|Southwest]] is predominantly a low-lying desert region. A portion known as the [[Colorado Plateau]], centered around the [[Four Corners]] region, is considered to have some of the most spectacular scenery in the world. It is accentuated in such national parks as [[Grand Canyon National Park|Grand Canyon]], [[Arches National Park|Arches]], [[Mesa Verde National Park|Mesa Verde]] and [[Bryce Canyon National Park|Bryce Canyon]], among others. Other smaller Intermontane areas include the [[Columbia Plateau]], which covers eastern [[Washington (state)|Washington state]], western [[Idaho]] and northeast [[Oregon]] and the [[Snake River Plain]] in southern Idaho.

The Intermontane Plateaus come to an end at the Cascade Range and the Sierra Nevada. The Cascades consist of largely intermittent, volcanic mountains, many rising prominently from the surrounding landscape. The Sierra Nevada, further south, is a high, rugged, and dense mountain range. It contains the highest point in the contiguous 48 states, [[Mount Whitney]] ({{convert|14505|ft|0|abbr=on|disp=or}}). It is located at the boundary between [[California|California's]] [[Inyo County, California|Inyo]] and [[Tulare County, California|Tulare]] counties, just {{convert|84.6|mi|1|abbr=on|disp=or}} west-northwest of the lowest point in North America at the [[Badwater Basin]] in [[Death Valley National Park]] at {{convert|279|ft|abbr=on|disp=or}} below sea level.<ref name=NED>{{cite web|url=https://catalog.data.gov/dataset/usgs-national-elevation-dataset-ned-1-meter-downloadable-data-collection-from-the-national-map-|title=USGS National Elevation Dataset (NED) 1 meter Downloadable Data Collection from The National Map 3D Elevation Program (3DEP) – National Geospatial Data Asset (NGDA) National Elevation Data Set (NED)|publisher=[[United States Geological Survey]]|date=September 21, 2015|access-date=September 22, 2015|archive-date=March 25, 2019|archive-url=https://web.archive.org/web/20190325085854/https://catalog.data.gov/dataset/usgs-national-elevation-dataset-ned-1-meter-downloadable-data-collection-from-the-national-map-|url-status=dead}}</ref> These areas contain some spectacular scenery as well, as evidenced by such national parks as [[Yosemite National Park|Yosemite]] and [[Mount Rainier National Park|Mount Rainier]]. West of the Cascades and Sierra Nevada is a series of valleys, such as the [[Central Valley (California)|Central Valley]] in California and the [[Willamette Valley]] in Oregon. Along the coast is a series of low mountain ranges known as the [[Pacific Coast Ranges]].

Alaska contains some of the most dramatic scenery in the country. Tall, prominent mountain ranges rise up sharply from broad, flat tundra plains. On the islands off the south and southwest coast are many volcanoes. Hawaii, far to the south of Alaska in the Pacific Ocean, is a chain of tropical, [[Volcanic island|volcanic islands]], popular as a tourist destination for many from [[East Asia]] and the mainland United States.

The territories of Puerto Rico and the U.S. Virgin Islands encompass a number of tropical isles in the northeastern [[Caribbean Sea]].  In the Pacific Ocean the territories of Guam and the Northern Mariana Islands occupy the limestone and volcanic isles of the Mariana archipelago, and American Samoa (the only populated US territory in the southern hemisphere) encompasses volcanic peaks and coral atolls in the eastern part of the [[Samoan Islands]] chain.{{refn|group=note|One island in American Samoa ([[Swains Island]]) is not in the Samoan Islands — it is in the [[Tokelau]] island chain.}}

The Atlantic coast of the United States is low, with minor exceptions. The Appalachian Highland owes its oblique northeast–southwest trend to [[Crustal deformation|crustal deformations]] which in very early geological time gave a beginning to what later came to be the Appalachian Mountain system. This system had its climax of deformation so long ago (probably in [[Permian]] time) that it has since then been very generally reduced to moderate or low [[Terrain|relief]]. It owes its present-day altitude either to renewed elevations along the earlier lines or to the survival of the most resistant rocks as residual mountains. The oblique trend of this coast would be even more pronounced but for a comparatively modern crustal movement, causing a depression in the northeast resulting in an encroachment of the sea upon the land. Additionally, the southeastern section has undergone an elevation resulting in the advance of the land upon the sea.

While the Atlantic coast is relatively low, the Pacific coast is, with few exceptions, hilly or mountainous. This coast has been defined chiefly by geologically recent crustal deformations, and hence still preserves a greater relief than that of the Atlantic. The low Atlantic coast and the hilly or mountainous Pacific coast foreshadow the leading features in the distribution of mountains within the United States.

The east coast Appalachian system, originally forest covered, is relatively low and narrow and is bordered on the southeast and south by an important coastal plain. The [[American cordillera|Cordilleran system]] on the western side of the continent is lofty, broad and complicated, having two branches, the Rocky Mountain System and the Pacific Mountain System. In between these mountain systems lie the [[Intermontane Plateaus]]. Both the [[Columbia River]] and [[Colorado River]] rise far inland near the easternmost members of the Cordilleran system, and flow through plateaus and intermontane basins to the ocean. Heavy forests cover the northwest coast, but elsewhere trees are found only on the higher ranges below the Alpine region. The intermontane valleys, plateaus and basins range from treeless to desert with the most arid region being in the southwest.

The Laurentian Highlands, the Interior Plains and the Interior Highlands lie between the two coasts, stretching from the [[Gulf of Mexico]] northward, far beyond the national boundary, to the [[Arctic Ocean]]. The central plains are divided by a hardly perceptible height of land into a [[Canada|Canadian]] and a United States portion. It is from the United States side that the great [[Mississippi River|Mississippi]] system discharges southward to the Gulf of Mexico. The upper Mississippi and some of the [[Ohio River|Ohio]] basin is the semi-arid prairie region, with trees originally only along the watercourses. The uplands towards the Appalachians were included in the great eastern forested area, while the western part of the plains has an arid climate supporting only scanty native plant life, and in the south, it is practically barren.

Elevation extremes:
*Lowest point: [[Death Valley]], [[Inyo County, California]]  {{convert|-280|ft|m|1|abbr=on}}
*Highest point: [[Denali|Denali/Mount McKinley]], [[Denali Borough, Alaska]]  {{convert|20310|ft|m|1|abbr=on}}