Source: US Global Legal Monitor
On September 3rd, 1783, the United States of America secured its independence from Great Britain by signing the Treaty of Paris. (Treaty of Peace, U.S.-U.K., September 3, 1783, 8 Stat. 80). Not only did this treaty bring an end to the Revolutionary War, but it also set the initial border between the United States and Canada, then known as British North America. This border, which stretched from modern-day Maine to the Lake of the Woods in modern-day Minnesota, for the most part still exists in the present day. The initial drafting of the border was not without its flaws, however, in large part due to the inaccurate maps of the time.
The border was supposed to reach the most northwestern part of the Lake of the Woods in Minnesota, and from there proceed due west to the Mississippi River. However, the Mississippi River’s headwaters are too far south of the Lake of the Woods to be intersected by a line drawn due west, a fact unknown at the time. Furthermore, at the other end of the border, in Maine, the border was drawn “From the North West angle of Nova Scotia viz [that is to say], that angle which is formed by a Line drawn due North from the Source of St. Croix River to the Highlands.” (Treaty of Peace, art. 2).
The 1794 Jay Treaty appointed a survey team to the Lake of the Woods and appointed two commissioners to adjudicate a dispute over the St. Croix River. (Amity, Commerce, and Navigation (Jay Treaty), U.S.-U.K., November 19, 1794, 8 Stat. 116.) Given that neither of these issues were resolved before the War of 1812 began between the two powers, the issues were again addressed in the 1814 Treaty of Ghent. (Peace and Amity (Treaty of Ghent), U.S.-U.K., December 24, 1814, 8 Stat. 218.) Along with bringing peace to the two nations, the Treaty of Ghent also made provisions for two new sets of commissioners to be appointed, one for each issue.
In 1818, the two nations signed the Convention of 1818. (Fisheries, Boundary, and Restoration of Slaves, U.S.-U.S., October 20, 1818, 8 Stat. 248). This treaty established the border west of the Lake of the Woods, which was to run along the 49th parallel to the Rocky Mountains, referred to in the treaty as the Stony Mountains. The border was drawn with a “Line drawn from the said Point [the most northwestern point of the Lake of the Woods] due North or South… until the said Line shall intersect the said Parallel of North Latitude [the 49th parallel]… and that the said Line shall form the Northern Boundary of the… United States.”
This remains the border to this day, though it is not without issues. Due to the wording of this treaty and the shape of the Lake of the Woods, a line drawn from the northwestern point of the lake led to the U.S. owning a small strip of land only accessible from Canada. Known as the Northwest Angle, there are a small number of U.S. citizens living there, who can only access their homes by land through Canada, though they can also travel over or through the Lake of the Woods. However, this is not the only part of the U.S. cut off from the mainland via treaty, as explained below.
The Aroostook War, named for skirmishes along the border, grew out of heightened tensions in the late 1830s. Both the British and American local governments mobilized militia forces, and General Winfield Scott was sent in to negotiate. The resulting agreement, the Webster-Ashburton Treaty of 1842, finally brought an end to the disputes over the Maine-Nova Scotia section of the border, establishing the modern path of the border in most of Maine. (Boundaries, Slave Trade, Extradition (Webster-Ashburton Treaty), U.S.-U.K., August 9, 1842, 8 Stat. 572).
In 1846, the Oregon Treaty was signed, which extended the 49th parallel past the Rockies to the Pacific, ending the dispute over the Oregon Territory. (Boundaries (Oregon Treaty), U.S.-U.K., June 15, 1846, 9 Stat. 869). This treaty would have two important ramifications. One was a second US exclave in Canada, and the other was another bloodless “war”, once again negotiated down by Winfield Scott. The exclave, Point Roberts, still exists today, and is home to another small US community, where the children must cross the border four times a day for schooling. It is a tourist destination for its novelty, as it is one of the few existing U.S. exclaves.
The Pig War took place on the San Juan Islands, in the straits between Washington and Vancouver Island. The Oregon Treaty had led to some ambiguity over who controlled the islands, so both British and U.S. settlers had established residence on the islands. At first, they peacefully coexisted, but eventually a U.S. settler killed a pig belonging to a British settler, as it had wound up on his property. This dispute between settlers led to British warships facing off against US troops who had rushed to the island. Winfield Scott was once again sent to negotiate down the tensions, and eventually the two powers agreed to a joint occupation of the islands until the dispute could be arbitrated by another power. The islands were eventually granted to the United States by the German Emperor in 1872 (see footnote 1 on page 123), but the occupation would continue for 12 years in the meantime.
Over the course of the centuries of border negotiations between the British and Americans, several separate commissioners had to be appointed to resolve various disputes along the border, from Passamaquoddy Bay and the St. Croix River in Maine to the Alaskan border in the late 1800s. In the early 1900s, in the Treaty of 1908, it came to pass that the two powers appointed yet another commission, charged with the task of more accurately determining and demarcating the border along its entire length. In 1925, this commission was made permanent, and it persists into the modern era. Known today as the International Boundary Commission, they are in charge of maintaining the border monuments, as well as keeping a 20-foot swath of land cleared along the entire length of the border and maintaining the official maps of the border.
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