Fifty-Four Forty or Fight was a slogan used during a boundary dispute between the United States and Britain. An 1818 treaty allowed both nations to occupy the Oregon Country, lying between 42 degrees and 54 degrees 40 minutes north latitude. In the 1830’s and 1840’s, American expansionists wanted to take the whole area, by force if necessary. In 1846, during James K. Polk’s presidency, the United States made a new treaty that set 49 degrees as a boundary, except for Vancouver Island. The United States secured the land south of the line, and Britain obtained the land to the north.
See also British Columbia (The border dispute); Polk, James Knox (“Oregon fever”).