One of the most striking things separating the United States and Canada is the line that divides the United States from Canada. While oceans, lakes, rivers, drainage basins, deserts, mountain ranges, and valleys dictate the size and shape of many nations, the pin-straight border running from Lake of the Woods to the Pacific Ocean is nothing if not completely and utterly arbitrary. The western half of the world’s longest land border was laid down in three stages: In 1783, an understandably cocksure Benjamin Franklin won British acceptance of a border extending from the “northwesternmost point” of Lake of the Woods to the Boundary Waters laid out in the Treaty of Paris, the denouement of the United States’ fight for independence. This border would have made much more sense if the source of the Mississippi River had been where both parties suspected, but then it was a botanist, not a professional cartographer, who had created the map negotiators were working from. In the aftermath of the second, wholly less conclusive war with Britain (the War of 1812), the forty-ninth parallel was established in the Anglo-American Convention of 1818 as the border between Lake of the Woods and the Stony [Rocky] Mountains. In this agreement, the point identified by Franklin was linked to the slightly more southerly forty-ninth parallel by a north-south line that would later form the boundary between present-day Manitoba and Ontario.
more from Grant Stoddard at The Walrus here.