Oregon Territory

In 1818 a US-British agreement established the 49th parallel from Lake of the Woods and east to the Rocky Mountains as the borders of Oregon Territory.  The two nations agreed to a 10 year joint occupation of the territory which was extended another 10 years in 1827.  By 1838, the ownership of the Oregon Territory had become quite controversial with the start of the migration along the Oregon Trail.

American expansionists urged that the US take control of Oregon and in 1844 Democrat James Polk ran for president under the platform "fifty-four or fight" referring to his hope of bringing a sizable portion of present day Vancouver and Alberta into the United States. The US and British had no desire to fight another war, so on June 15, 1846, the Oregon Treaty which was a compromise, was signed extending the US and Canadian border west along the 49th parallel just short of the Pacific Ocean.

The Treaty of Oregon Territory gave the US control over the future states of Oregon, Washington, Idaho, and Montana.  The British retained control of Vancouver Island and navigation right to part of the Columbia River.