Jewel Cave National Monument - South Dakota

Address:11149 Bldg B12, US Highway 16
Custer, South Dakota
Tel: (605) 673-2288

Jewel Cave is the second-longest cave in the world - and has not yet been fully explored. Discovered in 1900, the cave system is crammed with geological wonders arousing intense interest among serious scientists and the common visitor alike. When you step inside this underground world of bats, gypsum formations, calcite crystals, and a very rare formation called a hydromagnesite balloon, you will have a chance to walk or spelunk your way through these impressive geological formations.
Don't be fooled into thinking your trip will leave you entirely in the dark. On the surface of the park, trails lead you through Ponderosa pine forests and gorgeous wildflowers. If you're lucky, you may even catch a glimpse of a bald eagle along your journey.

With more than 133 miles surveyed, Jewel Cave is recognized as the third longest cave in the world. Airflow within its passages indicates a vast area yet to be explored. Cave tours provide opportunities for viewing this pristine cave system and its wide variety of speleothems including stalactites, stalagmites, draperies, frostwork, flowstone, boxwork and hydromagnesite balloons. The cave is an important hibernaculum for several species of bats.