Columbia River
This 2000 km river, roughly 800 km of which wends through Canada, has its source in southeastern British Columbia's Columbia Lake. It passes into the United States where it meets the Pacific Ocean at the divide between Washington and Oregon State.
Spanish explorers had named it Rio de San Roque in 1775, and it was called Oregon River by Jonathan Carver in 1766; it was not until 1792 that Boston trader Captain Robert Gray named it after his ship.1 David Thompson, then of the North West Company, explored the westward Columbia in 1811 to find American traders already present in Fort Astoria, on the south side of the Columbia's delta.2
As several early despatches show, this river served as a natural border between British and US interests until, after much tension in Oregon Territory, the Oregon Treaty of 1846 settled an enforceable borderline north of the Columbia to the 49th parallel, which is now the Canada-US border.
Mentions of this place in the documents