Lake Superior

Lake Superior, largest body of fresh water in the world, in east central North America, straddling the border between the United States and Canada. The deepest and westernmost of the five Great Lakes, Lake Superior is 560 km (350 mi) long and has a surface area of about 82,100 sq km (31,700 sq mi). The average depth of the lake is 147 m (483 ft), and the maximum depth is 406 m (1,332 ft). Lake Superior is bounded on the north and east by Ontario, on the south by Michigan and Wisconsin, and on the northwest by Minnesota. About two-thirds of the lake is in the United States.

Lake Superior has an irregular coastline, with a number of large bays; Keweenaw Peninsula, in Michigan, projects far into the lake. The northern lakeshore is fringed by bold, rocky cliffs, some rising 305 m (1000 ft) above the water surface. Near Munising, Michigan, on the southeastern shore, are the Pictured Rocks, multicolored sandstone cliffs, 15 to 91 m (50 to 300 ft) high, which in many places present fantastic forms. Several large forests border the lake, which receives many small streams, such as the Nipigon River, from the north, and the St. Louis River, from the west. The lake drains into Lake Huron, to the southeast, through the Saint Marys River, which is navigable via the Sault Sainte Marie Canals. Lake Superior has several large islands, notable among them Saint Ignace Island and Michipicoten Island, Ontario; Isle Royale, Michigan; and the Apostle Islands, Wisconsin.

The land near the lake, especially to the south and west, is rich in minerals, principally iron ore (hematite and taconite) and copper, nickel, and silver ores. These minerals, plus grain produced in the Prairie provinces of Canada and forest products, are shipped east via Superior and the rest of the Great Lakes-St. Lawrence Seaway system. Lake Superior very rarely freezes over, but ice along its shores closes its ports from December to mid-April. Major lakeports include Thunder Bay and Michipicoten Harbour, Ontario; Marquette and Copper Harbor, Michigan; Ashland, Wisconsin; Superior, Wisconsin-Duluth, Minnesota; and Two Harbors and Taconite Harbor, Minnesota. The first European to explore the lake was probably Étienne Brûlé, a French explorer, in 1622.