The Vermilion River rises in east central Illinois in Kankakee County and snakes its way in a generally northwesterly direction before emptying into the Illinois River at La Salle. It flows through Pontiac in Livingston County and Matthiesen State Park near Oglesby.
The river contains the only section of "whitewater" in northern Illinois. The section of river that contains "Wildcat Rapids" is located between Lowell and Oglesby. This is a "Class III" rapid and attracts canoeists and kayakers.