While hiking on the Hell Canyon Trail (on Black Hills National Forest land), one can spot an old boundary marker that reads: “Jewel Cave National Monument Boundary, 1936.” Jewel Cave’s boundary was once larger, and formed a perfect quadrilateral which included the southern portion of the present Hell Canyon Trail, the US Highway 16 switchbacks just west of the Historic Area, and another chunk of land on the southwestern border.

Jewel Cave became a National Monument on February 7, 1908. However, as more cave passageways began to be discovered more to the southeast on National Forest Land, a land swap was proposed. According to the Management Plan for Jewel Cave (1978), “Exploration work in the late 1950s and early 1960s located extensive passageways which extended to the southeast, out of the Monument boundaries.” Michael Wiles, Chief of Resource Management at Jewel Cave, explains that the monument’s boundary changed in 1965 because “exploration revealed cave passages extending southeast, beyond the original boundary, to what is now the Scenic Tour route. South Dakota Senators Mundt and Humphrey sponsored a bill to do an acre-for-acre land transfer between the NPS and the USFS, so that the NPS could develop and manage the newly discovered area.”

Today, there are numerous activities one can enjoy on the surface of Jewel Cave National Monument. Visitors can enjoy hiking, snowshoeing, wildflower viewing, and birding in addition to the various museum exhibits and park movie.

Cave tours at Jewel Cave are scheduled to resume in May 2020.

Jewel Cave Boundary Map, 1945

Current Jewel Cave Boundary Map