The Oregon Treaty is a treaty between the United Kingdom and the United States that was signed on June 15, 1846, in Washington, D.C. The treaty brought an end to the Oregon boundary dispute by settling competing American and British claims to the Oregon Country; the area had been jointly occupied by both Britain and the U.S. since the Treaty of 1818.
Background
The Treaty of 1818 set the boundary between the United States and British North America along the 49th parallel of north latitude from Minnesota to the "Stony Mountains" (now known as the Rocky Mountains). The region west of those mountains was known to the Americans as the Oregon Country and to the British as the Columbia Department or Columbia District of the Hudson's Bay Company. (Also included in the region was the southern portion of another fur district, New Caledonia.) The treaty provided for joint control of that land for ten years. Both countries could claim land and both were guaranteed free navigation throughout.
Joint control steadily grew less tolerable for both sides. After a British minister rejected the offer of U.S. Presidents James K. Polk and John Tyler to settle the boundary at the 49th parallel north, American expansionists called for the annexation of the entire region up to Parallel 54°40′ north, the southern limit of Russian America as established by parallel treaties between the Russian Empire and the United States (1824) and Britain (1825). However, after the outbreak of the Mexican–American War in April 1846 diverted U.S. attention and military resources, a compromise was reached in the ongoing negotiations in Washington, D.C., and the matter was then settled by the Polk administration (to the surprise of its own party's hardliners) to avoid a two-war situation, and another war with the formidable military strength of Great Britain.
Senate vote in June 1846
In early June 1846 the British offered to negotiate the boundaries between the United States and British North America in the region west of the Rockies. Some US senators such as Charles Gordon Atherton and Benning Wentworth Jenness were combative and were in favor of rejecting British proposals to negotiate. However others, such as both Alabama senators (Arthur P. Bagby and Dixon Hall Lewis) as well as both Massachusetts senators (Daniel Webster and John Davis) were in favor of accepting British proposals. The Senate agreed that they would vote on whether or not to recommend President Polk accept British offers to negotiate. Watching closely, the British hoped this vote would pass the Senate. On June 12, the Senate voted 38–12 recommending that President Polk accept British proposals to negotiate this boundary. Votes in favor included 18 Democrats and 20 Whigs, whereas 11 Democrats and one Whig voted against. Three Democrats and three Whigs abstained.
Negotiations
The treaty was negotiated by US Secretary of State James Buchanan and Richard Pakenham, British envoy to the United States. Foreign Secretary Earl of Aberdeen was responsible for it in Parliament. The treaty was signed on June 15, 1846, ending the joint occupation and making Oregonians south of the 49th parallel American citizens, with those north of it becoming British.
The Oregon Treaty set the border between the U.S. and British North America at the 49th parallel with the exception of Vancouver Island, which was retained in its entirety by the British. Vancouver Island, with all coastal islands, was constituted as the Colony of Vancouver Island in 1849. The U.S. portion of the region was organized as Oregon Territory on August 15, 1848, with Washington Territory being formed from it in 1853. The British portion remained unorganized until 1858, when the Colony of British Columbia was set up as a result of the Fraser Canyon Gold Rush and fears of the re-asserted American expansionist intentions. The two British colonies were amalgamated in 1866 as the United Colonies of Vancouver Island and British Columbia. When the Colony of British Columbia joined Canada in 1871, the 49th parallel and marine boundaries established by the Oregon Treaty became the Canada–US border.