The Retreat of Glaciers in the Midwestern U.S.
Maps -- 18,000 to 8,000 Years Ago
The five maps that follow trace the retreat of the glaciers of the last Ice Age. They begin with the glaciers at their maximum extent 18,000 years ago. By the time shown in the last map, 8,000 years ago, glaciers were no longer present in the midwestern United States. In addition, the maps show the extent and location of some of the lakes that formed as a result of the melting of the glaciers.
Key to Maps
Glaciers -- pale blue
Lakes -- blue
Salt Water -- dark blue (only 8,000 years ago)
14,000 years ago
12,000 years ago
10,000 years ago
8,000 years ago