Of all of the campgrounds that I have visited in Illinois, I would say that Rock Cut State Park is the best that I have seen. It boasts as being the largest State Park in Northern Illinois. It has a large lake with almost 40 miles of hiking trails, including equestrian trails and an equestrian campground. There is boating and fishing as well as swimming in the lake.
The campground staff is very helpful and do a good job at keeping it clean and well maintained even with the large number of visitors. Don't miss my interview with Marsha, one of the friendly staff members at Rock Cut State Park.