If you come to see an historic site it's fine. But if you come to hike you might be disappointed. It does need maintenance like another poster says. In summer mosquitoes are ridiculously savage because as an ancient flint quarry there are dozens of shallow pools of standing water that they breed in. I recommend seeing Flint Ridge for a little bit, visiting the gift shop and then for a serious hike driving 10 minutes to Taft Reserve on Flint Ridge Road, or to Black Hand Gorge. Or if the Ancient Ohio history is your thing, take Flint Ridge Road to Newark, Ohio and see the Newark Earthworks.
Hiked the Ravine Trail on the North side of Flint Ridge. A nice trail however could use some maintenance. Overgrown weeds and fallen down trail. It is a very level trail and well marked. Felt like a mile round trip. Very nice for a leisurely walk in the woods