Camp Ondessonk in Illinois is a beautiful camping spot surrounded by the Shawnee National Forest. Visitors can enjoy hiking and biking trails, rock climbing, and horseback riding. The campground has many amenities including restrooms, showers, and a camp store. Reservations are required for campsites, and there are over 100 sites available. The best time to visit is during the summer when temperatures average around 80 degrees Fahrenheit, but spring and fall are also great times to visit.