Onondaga Cave State Park

The main attraction is the cave, with cave tours available April through October.

There are several short hiking trails:
Blue Heron Trail 1 mi
Deer Run Trails 2.5 mi, great views from the bluff
Oak Ridge trail 3 mi

Vilander Bluff Trail 1.3 mi, is in a separate section of the park. At 200 ft, this is the highest bluffs on the Meramec.