Oregon Treaty

The Oregon Treaty of 1846 resolved a long-standing dispute between the United States and Great Britain over the Oregon Country, a vast region of the Pacific Northwest that the two nations had jointly occupied since 1818. Growing numbers of American settlers traveled the Oregon Trail in the 1840s, and expansionist sentiment, captured in the slogan "Fifty-four Forty or Fight," pressed the United States to claim the entire territory up to the Alaska boundary.

Rather than risk war while tensions with Mexico were rising, the administration of President James K. Polk negotiated a compromise with Britain. The treaty extended the boundary along the forty-ninth parallel from the Rocky Mountains to the Pacific, giving the United States the land to the south while Britain retained the territory to the north, including all of Vancouver Island.

The settlement peacefully divided the Pacific Northwest and fixed much of the present-day border between the United States and Canada. The American portion eventually formed the states of Oregon, Washington, and Idaho, along with parts of Montana and Wyoming. By avoiding conflict with Britain, the agreement allowed the United States to turn its attention to the war with Mexico that broke out the same year.