The Jewel of Our Nation's Caves

Orange-lit flowstone rocks making up the Formation Room at Jewel Cave National Monument
— National Park Service

Jewel Cave National Monument is home to one of the largest caves in the world.

It includes more than 180 miles of mapped and surveyed passages, but remains a mysterious underground wilderness that continues to intrigue scientists and explorers to this day. 

Discovering a natural wonder

White sharp crystal Dogtooth Spar at Jewel Cave National Monument

Dogtooth Spar formations

National Park Service

Tucked away in the Black Hills of South Dakota, the first recorded references of Jewel Cave trace back to 1900. Frank and Albert Michaud, a pair of prospectors who initially noticed a small opening in the canyon emitting drafts of cool air, filed a mining claim describing their discovery of the cave’s entrance. The opening was too small for human passage, but the two brothers enlarged it using dynamite, revealing a cavern lined with sparkling calcite crystals, hence the name “Jewel Cave.”

In the early 1900s, South Dakota was remote and sparsely populated. The Michauds' efforts to develop and market the cave as a tourist attraction were met with little success and they eventually sold their stake in the cave to the government.

Soon after, a local movement to set Jewel Cave aside for preservation led to the creation of Jewel Cave National Monument by President Theodore Roosevelt in 1908. The National Park Service began overseeing the cave in 1933 and in 1935, workers from the Civilian Conservation Corps established a camp at the cave to implement several key projects, including the construction of what would become a ranger cabin for the monument’s first permanent ranger.

Exploring the vast caverns

A caver with a helmet and headlamp walking through a brightly lit cave near Crushing Deep at Jewel Cave National Monument
Dan Austin/NPS

While the Michaud brothers' initial discovery was no doubt impressive, they almost certainly had no idea just how incredible it actually was. As recently as 1959, only 2 miles of Jewel Cave had been explored. The tours offered by the National Park Service were hardly attended, and public interest in what was thought to be a relatively small cavern had significantly diminished since the cave’s opening. 

But later in 1959, geologist Dwight Deal and rock-climbing enthusiasts Herb and Jan Conn began exploring farther in dedicated effort to map new passages. By 1961, they had explored and mapped more than 15 miles. That number has continued to grow thanks to subsequent explorations, and the known length of Jewel Cave currently spans more than 180 miles, making it the third longest cave in the world. Experts suspect that the explored portion of the cave accounts for only a fraction of its actual size.

Visiting Jewel Cave

A sign saying "Hell Canyon / Canyons Trail" with green grass and pine trees in the background at Jewel Cave National Monument
Mike Hittle/NPS

A sizable section of Jewel Cave is open to the public, and all cave tours are ranger-guided. The cave contains many of the most common types of speleothems (cave formations), including calcite formations like stalactites, stalagmites, flowstone, and frostwork, along with gypsum needles, beards, and flowers. Jewel Cave also contains very rare formations known as hydromagnesite balloons, which are created when gas from an unknown source inflates a soft layer of magnesium carbonate hydroxide minerals to create a balloon-like structure. 

Above ground, Jewel Cave National Monument also offers a wide range of surface activities, including guided nature hikes, talks, and demonstrations. The monument encompasses more than 1,200 acres of lush Ponderosa pine forest, and hiking trails of varying difficulty are available to traverse this wooded landscape, which also harbors more than 120 bird species and vibrant spring wildflowers.

Visiting Jewel Cave National Monument is a one-of-a-kind experience, and the National Park Service is proud to preserve this stunning natural marvel. As you experience this South Dakotan national parks, share your discoveries with us at and connect with other adventurers on Facebook, Twitter, Instagram, and Tumblr by using #FindYourPark and #EncuentraTuParque.


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