The Northwest Angle is the U.S. pene-exclave in Minnesota cut off from the rest of the state by the Canada–United States border.
It occupies the northern part of Lake of the Woods County and is separated from mainland Minnesota by the lake and Canadian territory. The Angle shares a land border with Manitoba, while its waterways connect it geographically to the rest of Minnesota. It can be reached domestically by boat, aircraft, or seasonal ice road; driving by ordinary roads usually requires passing through Canada twice.
The region exists because 18th-century mapmakers misunderstood the shape of Lake of the Woods and the location of the Mississippi River's headwaters. The 1783 Treaty of Paris referred to the lake's “northwesternmost point,” and later surveys and treaties clarified the boundary. The Anglo-American Convention of 1818 established the 49th parallel westward from the lake.
The Northwest Angle is often confused with Elm Point, another nearby Minnesota pene-exclave, but Elm Point is a small cape rather than the principal community and region described in the question. Point Roberts and Alburgh Tongue are pene-exclaves in Washington and Vermont, respectively.