Minnesota's Northern Border: The "Northwest Angle" Explained

Why Minnesota Has a Distinctive Northern Protrusion

Minnesota's northern boundary isn't a straight line—it features a notable protrusion known as the Northwest Angle (or simply "the Angle"), the only part of the contiguous U.S. north of the 49th parallel.

Historical Origins

This geographic anomaly stems from the 1783 Treaty of Paris, which ended the American Revolutionary War. The treaty defined the U.S.–British North America border as extending westward from Lake of the Woods to the Mississippi River. Negotiators relied on flawed maps (notably the Mitchell Map) that misrepresented the lake's geography and the Mississippi's source.

Subsequent Treaties

The 1818 Convention established the 49th parallel as the border west of Lake of the Woods. The 1842 Webster-Ashburton Treaty confirmed the Angle's inclusion in the U.S., rather than ceding it to Britain (Canada) for a cleaner boundary.

Geographic Reality

The Angle is a 123-square-mile peninsula (plus islands) accessible by land only through Manitoba, Canada, or by boat across Lake of the Woods. Its ~120 residents are part of Angle Township, Lake of the Woods County.

Not a "Spike," but a Historic Quirk

While often called a "spike," it's more accurately a rectangular protrusion resulting from 18th-century cartographic error and diplomatic compromise—a unique fingerprint on the map.