“Camp Ondessonk is owned and operated by the Catholic Diocese of Belleville, Illinois. Christian traditions and teachings guide the work of the this ministry. People of all faiths are encouraged and welcome to enjoy the Ondessonk experience.”
From the Ondessonk page. https://ondessonk.com/home/ondessonk-experience/
983 acres adjacent to the Shawnee. Open to visitors in the off season.
This is a private area, you MUST drive to the office & register upon entering & leaving. After that you have the run of the place in the off season. Very friendly staff and they have free maps.
Nice trails, and great sights.
My wife & I visited a couple of weeks ago and had a great time just wandering through the trails and enjoying the scenery. We missed the slot canyon area, I guess that means we have to go back. We would love to see the cascades & waterfalls, but we are having a drought right now. Great place to be a kid at camp. I seem to have gotten gypped as a kid. Our scout troop never even went to a woods. Great daytrip with kids.