As the glaciers were retreating, people moved into the area c. 8,000 BC to hunt for mastodon and mammoths at the glacier’s edge. Early people shifted their camps seasonally to be closer to needed resources but repeatedly returned to this area for thousands of years.The Garrison Site is adjacent to the channelized North Branch of the Chicago River and the area had a rich ecosystem. The high, dry ground between swamps and marshes supported bountiful water fowl, small mammals, mussels, turtles, wild rice, water lily seeds and plant tubers. The savanna and forest areas had deer, antelope, acorns, hazelnuts and walnuts. The abundance of plants and animals was ideal for hunters and gatherers.
