Was Minnesota's 'Northwest Angle' formed due to a 1783 survey error?
Minnesota’s Northwest Angle is separated by water from the rest of the state, but a surveying error led to it becoming part of Minnesota rather than Canada, according to research compiled by the Minnesota Historical Society.
Using outdated mappings of what is now northern Minnesota, the 1783 Treaty of Paris determined a U.S.-Canada border from the Atlantic to the Mississippi River. The Northwest Angle and Lake of the Woods were believed to be adjacent to the Mississippi headwaters.
In 1798, British explorers found the headwaters to be farther south. By the time the region was officially surveyed by a joint British-American commission in 1824 and 1825, the scale of the Louisiana Purchase had already determined that the Northwest Angle and Minnesota belonged to the United States.
In the 1980s, residents of the Angle threatened to secede from the United States, citing fishing disputes and neglect from the government.