The Kaskaskia River rises in Champaign County and flows about 300 miles in a southwesterly direction emptying into the Mississippi River near Old Fort Kaskaskia in Randolph County.

It is the source of Lake Shelbyville and Carlyle Lake and has spawned numerous state parks and wildlife management areas including Eagle Creek State Park, Wolf Creek State Park, Eldon Hazlet State Park and South Shore State Park.