Ohio Caverns is a show cave located 30 miles from Dayton, Ohio near West Liberty, in Salem Township, Champaign County, Ohio in the United States. A popular tourist destination and member of the National Caving Association, it is the largest of all the cave systems in Ohio and contains many crystal formations. Approximately 90% of its stalactite and stalagmite formations are still active. The cavern system was originally an aquifer, holding an underground river of melted glacier water.