Topography and climate The plains to the west, the Appalachians to the east, bisected by a Mississippi swollen with glacial meltwater. To the north lay the Great Lakes, bordered by retreating glaciers that had left their mark on the hills and plains in what is now Ohio, Illinois, and Indiana. Ice gripped upper Minnesota, Michigan, and Wisconsin.
Winters were cold, summers warm but short. Environments could shift dramatically over a short distance, with tundra quickly giving way to forest. After 11,500 years ago, the weather slowly shifted to today’s conditions, interrupted by a frigid, dry regime between 10,900 and 10,100 years ago.
When the first people arrived Evidence suggests sometime around 13,500 years ago.
Likely routes to the region Through northwest tundra or traversing the western prairies. next >>