in 1846 the oregon territory was acquired in a compromise with
Oregon Treaty The Oregon Treaty[1] is a treaty between the United Kingdom and the United States that was signed on June 15, 1846, in Washington, D.C. Signed under the presidency of James K. Polk, 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.