Editing Louisiana Purchase (section)

==Boundaries==
A dispute soon arose between Spain and the United States regarding the extent of Louisiana. The territory's boundaries had not been defined in the 1762 Treaty of Fontainebleau that ceded it from France to Spain, nor in the 1801 Third Treaty of San Ildefonso ceding it back to France, nor the 1803 Louisiana Purchase agreement ceding it to the United States.{{sfnp|Schoultz|1998|pp=15–16}}

[[File:U.S. Territorial Acquisitions.png|thumb|upright=2.0|left|The Purchase was one of several territorial additions to the U.S.]]

The U.S. claimed that Louisiana included the entire western portion of the Mississippi River [[drainage basin]] to the crest of the Rocky Mountains and land extending to the [[Rio Grande]] and [[West Florida]].{{sfnp|Haynes|2010|pp=115–116}} Spain insisted that Louisiana comprised no more than the western bank of the Mississippi River and the cities of New Orleans and St. Louis.{{sfnp|Hämäläinen|2008|p=183}} The dispute was ultimately resolved by the [[Adams–Onís Treaty]] of 1819, with the United States gaining most of what it had claimed in the west.

The relatively narrow Louisiana of New Spain had been a special province under the jurisdiction of the [[Captaincy General of Cuba]], while the vast region to the west was in 1803 still considered part of the Commandancy General of the [[Provincias Internas]]. Louisiana had never been considered one of New Spain's internal provinces.{{sfnp|Weber|1994|pp=223, 293}} If the territory included all the tributaries of the Mississippi on its western bank, the northern reaches of the purchase extended into the equally ill-defined British possession—Rupert's Land of [[British North America]], now part of Canada. The purchase originally extended just beyond the [[50th parallel north|50th parallel]]. However, the territory north of the 49th parallel (including the [[Milk River (Alberta–Montana)|Milk River]] and [[Poplar River (Montana–Saskatchewan)|Poplar River]] watersheds) was ceded to the UK in exchange for parts of the [[Red River Basin]] south of [[49th parallel north|49th parallel]] in the [[Treaty of 1818|Anglo-American Convention of 1818]].<ref>{{usstat|8|248}}</ref><ref>{{cite web |url=https://2009-2017.state.gov/documents/organization/83046.pdf |title=Treaties in Force |publisher=[[United States Department of State]] |access-date=July 14, 2015 }}</ref>

The eastern boundary of the Louisiana purchase was the Mississippi River, from its source to the [[31st parallel north|31st parallel]], though [[Lake Itasca|the source of the Mississippi]] was, at the time, unknown. The eastern boundary below the 31st parallel was unclear. The U.S. claimed the land as far as the [[Perdido River]], and Spain claimed that the border of its Florida Colony remained the Mississippi River. The Adams–Onís Treaty with Spain resolved the issue upon ratification in 1821. Today, the 31st parallel is the northern boundary of the western half of the [[Florida Panhandle]], and the Perdido is the western boundary of Florida.<ref>{{Cite web|url=http://www.leg.state.fl.us/statutes/index.cfm?submenu=3#A2S01|title=Statutes & Constitution :Constitution : Online Sunshine|website=leg.state.fl.us|access-date=2020-03-20}}</ref>

Because the western boundary was contested at the time of the purchase, President Jefferson immediately began to organize four missions to explore and map the new territory. All four started from the Mississippi River. The [[Lewis and Clark Expedition]] (1804) traveled up the [[Missouri River]]; the [[Red River Expedition (1806)]] explored the Red River basin; the [[Pike Expedition]] (1806) also started up the Missouri but turned south to explore the [[Arkansas River]] watershed. In addition, the [[Dunbar and Hunter Expedition]] (1804–1805) explored the [[Ouachita River]] watershed.<ref>{{Cite book |last=Dunbar |first=William |url=https://books.google.com/books?id=NHiOAwAAQBAJ |title=The Forgotten Expedition, 1804–1805: The Louisiana Purchase Journals of Dunbar and Hunter |date=2006 |publisher=Louisiana State University Press |isbn=978-0-8071-5974-3 |location=Baton Rouge |pages=xi–xii |oclc=890944426}}</ref> The maps and journals of the explorers helped to define the boundaries during the negotiations leading to the Adams–Onís Treaty, which set the western boundary as follows: north up the [[Sabine River (Texas–Louisiana)|Sabine River]] from the Gulf of Mexico to its intersection with the [[32nd parallel north|32nd parallel]], due north to the [[Red River of the South|Red River]], up the Red River to the [[100th meridian west|100th meridian]], north to the Arkansas River, up the Arkansas River to its headwaters, due north to the [[42nd parallel north|42nd parallel]] and due west to its previous boundary.<ref name="Klein-LoC" />