The northwestern part of the United States is known as the Pacific Northwest, encompassing the states of Washington, Oregon, and Idaho. Extreme western Montana, located near Missoula, Montana, is also generally considered to be part of this region.

Residents of the south coast of British Columbia, Canada often consider themselves to be part of the Pacific Northwest. There is considerable cultural interchange and much shared history between this part of Canada, and their American counterparts directly to the south.

From the 1810s until the 1840s, modern-day Washington, Oregon, Idaho, and western Montana, along with most of British Columbia, were part of the Oregon Country, which was jointly administered by the United States and the United Kingdom.