The Kankakee River is a tributary of the Illinois River, approximately 133 miles (214 km) long, in the Central Corn Belt Plains of northwestern Indiana and northeastern Illinois in the United States. At one time, the river drained one of the largest wetlands in North America and furnished a significant portage between the Great Lakes and the Mississippi River. Significantly altered from its original channel, it flows through a primarily rural farming region of reclaimed cropland, south of Lake Michigan.

The Illinois River is a principal tributary of the Mississippi River at approximately 273 miles (439 km) in length. Located in the U.S. state of Illinois, the river has a drainage basin of 28,756.6 square miles (74,479 km2). The Illinois River begins with the confluence of the Des Plaines and Kankakee rivers in the Chicago metropolitan area, and it generally flows to the southwest across Illinois, until it empties into the Mississippi near Grafton, Illinois. Its drainage basin extends into southeastern Wisconsin, northwestern Indiana, and a very small area of southwestern Michigan in addition to central Illinois. Along its shores are several river ports, including Peoria, Illinois. Historic and recreation areas on the river include Starved Rock, and the internationally important wetlands of the Emiquon Complex and Dixon Waterfowl Refuge.