Concealed beneath the rolling farmland and wooded countryside of Champaign County, Ohio, the caverns were formed thousands of years ago when an underground river cut through ancient limestone and created vast rooms and passageways that later filled with countless crystal stalactites, stalagmites and other amazing formations.
Today, these once-hidden caves are one of Ohio's top tourist attractions — a place unlike anywhere else in the nation, and within an easy day-trip drive of anyplace in the state. The caverns remain a steady 54 degrees year-round, regardless of the surface temperature. The humidity is always above 90 percent, and the air inside the caverns is cleaner than the air above ground — filtered by the water that formed the caves and still drips today. The caverns are the largest in the state, with over 2 miles of surveyed passageways ranging in depth from 30 feet to the deepest point of 103 feet. Special tours take you into the "historic" part of the cave — the portion first discovered and opened decades ago.