The cave was discovered in 1929 by two loggers and the first commercial tours started in 1930. Over the years, extensive exploration and development has opened more than two dozen rooms that are featured in the cave. Formations include stalactites, stalagmites, dogtooth spar, popcorn crystals, boxwork crystals and flowstone. Located south of Deadwood, Wonderland Cave is open seasonally, May through October. Find more information on our website and Facebook page.