Glacial Lake Wisconsin was a prehistoric proglacial lake that existed approximately 15,000 years ago, at the end of the last ice age, in the central part of present-day Wisconsin in the United States.

The lake was formed by melting of the area of the glacier called the Driftless Zone, which extended into central Wisconsin. As the glacier melted, an ice dam formed the lake, which was approximately the same size as the Great Salt Lake in Utah, and up to 150 ft (45 m) deep.

The eventual sudden bursting of the ice dam caused a catastrophic flood that formed the Dells of the Wisconsin River in pre-existing Cambrian sandstone on the south edge of the lake. The resulting flood lowered the level of the lake to approximately 50 ft (15 m).

See also

• List of prehistoric lakes
• Lake Wisconsin

Former lakes | Geography of Wisconsin | History of Wisconsin