Rock Creek is a 24.7-mile-long (39.8 km)[1] tributary of the Kankakee River in the U.S. state of Illinois. It empties into the Kankakee River in Kankakee River State Park which is just north west of the city of Kankakee. It starts in higher land and then drops into the Kankakee River Valley. Because of this, the river has cut through the rock, forming a gorge. The majority of this gorge is in the state park. There is also a trail in Kankakee River State Park that follows Rock Creek.Rock creek waterfalls area is a popular summer destination for the local residents who know of its location approx 1.5 miles upstream from the main entrance of the state park.The cliffs can reach as high as 80 feet high in this area from the park entrance to the falls.Its a very popular small mouth fishing destination for many northern and central area Illinois residents.