Two competing theories explain the tunnel s formation. One is that the water cut through the mountain at this point and found the canyon on the other side as the easiest path downstream. The other is that the canyon was formed originally as part of the large cave. Over time, the roof collapsed over most of the cave leaving a tunnel connecting to a small canyon. The state of Virginia has purchased the land around the tunnel and operates a state park at the site.
Visitors arrive at a parking lot on top of the ridge.
A small visitors center contains historical and geological exhibits describing the tunnel and a gift shop with the usual tourist stuff. A chair lift operates on the weekends to take visitors to the base of the canyon. Recently, the state has installed lights around the tunnel and opens the park at night once or twice a month. The park has a few miles of trails leading to overlooks and a campground area. The best walk to take in the park is from the visitors center to the tunnel.