Treaty of 1818
formal, binding written agreement entered into by the United Kingdom and the United States in international law
The Convention respecting fisheries, boundary and the restoration of slaves, also known as the London Convention, Anglo-American Convention of 1818, Convention of 1818, or simply the Treaty of 1818, is an international treaty signed in 1818 between the United States and the United Kingdom. This treaty resolved long-standing boundary issues between the two signatories. The treaty allowed for joint occupation and settlement of the Oregon Country, known to the British and in Canadian history as the Columbia District of the Hudson's Bay Company, and including the southern portion of its sister district New Caledonia.
The two signatories agreed to a boundary line involving the 49th parallel north to the Rocky Mountains because a straight-line boundary would be easier to survey through the Great Plains, than the pre-existing boundaries based on watersheds. The treaty marked both the United Kingdom's last permanent major loss of territory in what is now the continental United States and the United States' first and only permanent significant cession of North American territory to a foreign power, until the Webster–Ashburton Treaty of 1842.
The British ceded all of Rupert's Land south of the 49th parallel and east of the Continental Divide, including much of the Selkirk Concession, which became the basis of the Red River Colony, south of that latitude. The United States ceded only a small portion of the Milk River region on the northernmost edge of the Missouri Territory north of the 49th parallel.
Provisions
The treaty name is variously cited as
"Convention respecting fisheries, boundary, and the restoration of slaves",
"Convention of Commerce (Fisheries, Boundary and the Restoration of Slaves)",
and "Convention of Commerce between His Majesty and the United States of America".
Article I secured fishing rights along Newfoundland and Labrador for the US.
Article II set the boundary between British North America and the United States along "a line drawn from the most northwestern point of the Lake of the Woods, [due south, then] along the 49th parallel of north latitude..." to the "Stony Mountains" (now known as the Rocky Mountains). Britain ceded all territory south of this new boundary, including portions of the Red River Colony and Rupert's Land (comprising parts of the present states of Minnesota, North Dakota, and South Dakota).
This brief starts where responsible research should: with the source description of “Treaty of 1818” as formal, binding written agreement entered into by the United Kingdom and the United States in international law. Everything that follows is an evidence route, not borrowed authority.
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The subject matters to the history & society register because the source frames it as formal, binding written agreement entered into by the United Kingdom and the United States in international law. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Chronology, provenance and viewpoint should be read together before a broad social or political interpretation is accepted. The source revision retrieved here is dated Sep 24, 2026. The linked authority identifier is Q649599. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1818 and 1842.
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This entry incorporates text from “Treaty of 1818” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.