Lake Michigan Facts

Lake Michigan is the only Great Lake entirely contained within the United States. The lake borders Michigan, Wisconsin, Illinois, and Indiana. Connected to Lake Huron through the Straits of Mackinac, the two lakes technically behave like one big water body.

Lake Michigan Basin Statistics
  • Length: 307 mi (494 km)
  • Breadth: 118 mi (190 km)
  • Elevation: 577.5 ft (176 m)
  • Depth: 279 ft (85 m) average; 923 ft (281 m) maximum
  • Volume: 1,180 cubic mi (4,918 cubic km)
  • Water surface area: 22,300 square mi (57,753 square km)
  • Drainage basin area: 45,600 square mi (118,095 square km)
  • Shoreline length: 1,640 mi (2,639 km), including islands
  • Outlet: Straits of Mackinac to Lake Huron
  • Retention or replacement time: 62 years
  • Population: 12+ million; this includes metropolitan Chicago, which is not part of the drainage basin, but uses Lake Michigan for drinking water.
Lake Michigan Basin

Lake Michigan Basin

Source:Michigan Sea Grant.