The 1846 Oregon Treaty, formally titled Treaty with Great Britain, in Regard to Limits Westward of the Rocky Mountains, established the border between the British and American sections of the Oregon Country. The Oregon Country had been jointly occupied by both the British and Americans since the Anglo-American Convention of 1818 when they established a joint claim over the region. This arrangement steadily grew intolerable for both sides. American President James Polk ran on the platform "Fifty-Four Forty or Fight!" in the 1844 election; 54°40' referred to the latitude line that formed the northern border of the Oregon Country.

The treaty was negotiated by James Buchanan, U.S. Secretary of State, and Richard Pakenham , a member of Queen Victoria's privy council and envoy to the U.S. The treaty was signed in Washington D.C. on June 15, 1846.

The Treaty states that the 49th parallel will form the border of the United States and the British on the mainland. Vancouver Island was an exception that was given to the British in its entirety despite going south of the 49th parallel. The 49th parallel became the US-Canadian border when British Columbia became part of Canada.

The U.S. portion of the region was organized as the Territory of Oregon on August 14, 1848.

The treaty defined the border in the Strait of Juan de Fuca through the major channel. Due to difference in where the major shipping channel was, British and Americans had both settled on the same islands. In 1859, an unclear description of the border in the treaty later led to the Pig War over the ownership of the San Juan Islands.

External link

• Text of Treaty from the Avalon Project