Off season
Onondaga Cave State Park has a very well maintained, long campground. It meanders through a hilly area and affords campers with several locations to have some privacy from other nature seekers and the inevitable bring the kitchen sink campers too. The lower campsite is prone to flooding but has direct river access.
Unfortunately we arrived the week after the Onondaga Cave had closed for the season to let the resident bats get some well deserved hibernation privacy and quiet. We were still able to enjoy the many trails offered and fall colors just ramping up. The campground is off I44 outside St Louis, Mo and surrounded by several other parks including part of the Mark Twain National Forest.
Showerhouse facilities were small but well maintained and decorated by the local high school and laundry facilities were on site. Keep your pup leashed even on site and watch for local wildlife which may show up at your doorstep.