National Park Service, South Dakota.
Immerse yourself in one of the longest caves in the world. With over 215 miles of mapped and surveyed passages, this underground wilderness appeals to human curiosity. Its splendor is revealed through fragile formations and glimpses of brilliant color. Its maze of passages lures explorers, and its scientific wealth remains a mystery. This resource is truly a jewel in the National Park Service.
By car: Jewel Cave National Monument is located 13 miles west of Custer, South Dakota and 24 miles east of Newcastle, Wyoming on U.S. Highway 16. The monument is about 54 miles from Rapid City, South Dakota via U.S. Highway 16 / 385. By plane: The nearest major airport, Rapid City Regional Airport, is 63 miles away.