Oregon boundary dispute

The 19th-century dispute between the United States and Britain over the boundary and control of the Oregon Country, settled by the Oregon Treaty of 1846.

Oregon Country: A region of the Pacific Northwest claimed by several powers before the United States and Britain divided it in 1846. The dispute concerned sovereignty over this region and the line that would divide it.
Oregon Treaty: The 1846 agreement that established the United States–British boundary at the 49th parallel west of the Rocky Mountains. It ended the dispute by setting the boundary and defining arrangements for shared interests.
54°40′ or Fight: A slogan advocating the United States' claim to the Oregon Country as far north as latitude 54°40′. The settlement stopped far south of this maximal claim, despite the slogan's prominence.
Oregon Territory: A United States organized territory established in 1848 in lands acquired through the Oregon Treaty. The treaty's southern portion became the basis for American territorial government.
Treaty of 1818: An agreement between the United States and Britain that established joint occupation of the Oregon Country. Its temporary arrangement postponed a boundary decision and allowed rival claims to persist.
49th parallel north: A circle of latitude 49 degrees north of the equator, used as part of several international boundaries. The treaty adopted this line westward to the Strait of Georgia.
Nootka Crisis: An international confrontation in the late 18th century over competing claims to the Pacific Northwest coast. It illustrates earlier European rivalry over the region that later became the subject of the boundary dispute.
Vancouver Island: A large island off the Pacific coast of Canada, separated from the mainland by the Strait of Georgia. The treaty left the island under British control despite the boundary's approach to its shores.
Astoria, Oregon: A settlement at the mouth of the Columbia River founded by John Jacob Astor's Pacific Fur Company in 1811. Its transfer from British to American control became an early symbol of competing claims.
James K. Polk: The 11th president of the United States, who served from 1845 to 1849. His administration negotiated the treaty while pressing the American claim to Oregon.

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Texas annexationRelated: The dispute shows how U.S. expansion under Polk involved diplomacy as well as annexation and war.