1846 – The Oregon Treaty is signed

The area known as the Oregon Country originally encompassed a much larger area of land than is now occupied by the state of Oregon. On the American side of the border, t took in the states of Washington and Idaho, as well as parts of Wyoming and Montana. On the Canadian side, it took in Vancouver Island, and parts of mainland British Columbia. And where the border was to be drawn was a subject of dispute for half a century after the war of 1812 and the treaty of 1818.

The matter was finally settled with the signing of the Oregon Treaty in Washington D.C., which set the boundary at the 49th parallel (i.e. latitude 49 degrees north), with the exception of Vancouver Island, which straddles the parallel, and was given to Canada in its entirety. This represented a backdown for the Democratic Party that counted President Polk as its leader, as they had campaigned on the slogan “54 40 or Fight!”, asserting a claim to the territory as far north as 54 degrees 40 minutes – the southernmost latitude of what is now Alaska (and was then Russian America).

Referenced in:
James K. Polk — They Might Be Giants