Cache River State Natural Area is a state nature preserve and recreational area located in Belknap, Illinois. It features a variety of ecological and geological features unique to this area of the world. It is part of the Illinois State Park system and is operated and managed by the Illinois Department of Natural Resources.

Cache River State natural Area is located in the Cache River Valley, an area known for its unique wetlands and diverse habitats. A park visitor can clearly see four unique ecological areas in the park. People in the area can find well preserved natural communities and habitats. People in the area have exerted a lot of effort to protect the Cache River watershed.

This 14,791 acre natural preserve offers many outdoor recreational activities including fishing, hiking, wildlife viewing, among others.