Rushmore Cave

Mt. Rushmore Cave - Beautiful Rushmore Cave - Rush Mountain Adventure Park

Useful Information

Location: 13622 Hwy 40, Keystone, SD 57751.
Near Keystone, about 10 km east of Mount Rushmore State Memorial on State Highway 40.
(43.873255, -103.331139)
Open: MAR Sat, Sun 9-17.
APR to mid-MAY Fri-Sun 9-17.
Mid-MAY to MAY daily 9-17.
JUN to mid-AUG daily 10-18.
Mid-AUG to AUG Wed-Sun 10-18.
SEP Thu-Sun 9-17.
OCT Fri-Sun 9-17.
Fee: Adult USD 20, Children (5-12) USD 15, Children (0-4) free.
Classification: SpeleologyKarst cave
Light: LightIncandescent Electric Light System
Dimension: T=14 °C, H=98 %, A=1197 m asl.
Guided tours: D=60 min, L=800 m.
Photography: allowed
Accessibility: no
Address: Rush Mountain Adventure Park, 13622 Hwy. 40, Keystone, SD 57751-6604, Tel. +1-605-255-4384. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


1874 a military expedition led by George A. Custer finds gold in French Creek.
1876 cave discovered by placer miners.
1927 opened to the public by the Ferguson family.
1952 sold to Si and Ruth Pullen, renamed Rushmore Cave, and reopened.
1956 electric light installed.
1960 gift shop built.
1969 exit tunnel built.
2008 sold to a group of four partners, all residents of the Black Hills, converted into Rush Mountain Adventure Park.


A formation in Rushmore Cave with a blueish colour caused by copper.

Rushmore Cave is quite famous, mainly because of its location. Just a few kilometers from Mt. Rushmore, the giant sculpture of the heads of four American presidents, this cave participates on the Mt. Rushmore visitors. On the way to the main sight, many visitors see the roadside cave and make a stop. Actually that's what happened to me and my family when I visited the cave on a family holiday.

Rushmore Cave is open as a show cave for almost 100 years. Although the name never changed completely, it was somewhat adapted over time, and so it was known as Mt. Rushmore Cave, Beautiful Rushmore Cave, and now Rush Mountain Adventure Park. The whole story started in 1874 with a military expedition led by George A. Custer found gold in French Creek. The Black Hills were opened to miners and settlers. Mining camps and towns sprung up all around the Black Hills, one of them was named Hayward, named after the miner Charles Hayward. They were doing placer mining, where gravel was flushed away with water. So they needed a lot of water, which had to be brought from miles away using a series of wooden waterways, called flumes. One of those flumes passed along the hillside directly above the cave, and when the flume broke and the water disappeared into a small hole in the hillside, and the cave was discovered. The miners widened the hole and lowered themselves in what is now known as the Entrance Room.

The miners visited the cave, but there were no valuable minerals, so they ignored it. But their children explored its passages, and soon they showed it to others, and more people became interested in the cave and came to see it. The ground was owned by the Ferguson family, and in 1927 they officially opened the cave as a show cave named Hermosa Crystal Cave. The town grew to a few thousand inhabitants, but when the deposit was exhausted, the people moved away. Today the village is completely gone, only the cemetery remains. The cave was closed due to World War II.

Soon after World War II, the cave was sold in 1952 to Lester “Si” and Ruth Pullen of Spencer, Iowa. They renamed it Rushmore Cave to take advantage of the growing popularity of Mount Rushmore and reopened it. The first tours in 1952 were given with kerosene lanterns 24 hours a day. They updated the cave and the property with electric light, a new gift shop, an exit tunnel and more. They operated the cave as a family business for 55 years. Over time, they renamed the cave Mt. Rushmore Cave and Beautiful Rushmore Cave, as far as we know with little success.

When the Pullens finally retired in 2008 they sold the cave to a group of four partners, all residents of the Black Hills. The new owners renamed the cave back into Rushmore Cave, but they then added a theme park with a dozen different rides. The cave is now only one of numerous attractions. They are called the Soaring Eagle Zipline Ride, Gunslinger 7D Interactive Dark Ride, the Rushmore Mountain Coaster and the Wingwalker Challenge Course. They also added a lunch/snack venue called Sparky’s Snackitorium.

Rushmore Cave participated from the popularity of Mt. Rushmore, but nevertheless it is a really interesting cave. The geological situation in the Black Hills is unique, as the pahasapa limestone contains various interesting ore veins. Those orebodies were caused by the granite of Mt. Rushmore, which was slowly pushed up from 60 to 40 million years ago. The Mississippian limestone (360 to 330 Ma) was karstified for the first time soon after its formation. But then the limestone and the caves were buried by other layers of sedimentary rock, they were inactive and inaccessible for 260 Ma. But then a plume of magma was rising through the sedimentary rocks which were subjected to lifting and deformation which caused cracks. The groundwater was heated by the hot magma and the slowly circulating, acidic groundwater deposited hydrothermal minerals and ores in the cracks. The minerals and ores, corroded and oxidized by the water, produced fascinating colorful limestone formations. The strange and rare minerals all around Rushmore Cave are exciting.