Living off-grid to map 62 miles of Jewel Cave: The Conn legacy

The Conns’ Underground Quest That Rewrote Caving History

Jewel Cave National Monument in South Dakota exists because two people said they’d try caving “once” in 1959.

Jan and Herb Conn agreed to help their friend explore what seemed like a small, unremarkable cave that officials thought might not deserve monument status. That single trip became a 22-year obsession.

Living off-grid in their stone home called Conncave, they spent over 6,000 volunteer hours mapping 62 miles of underground passages.

Herb financed their expeditions by working on Mount Rushmore while Jan crawled through spaces they named Torture Chamber and Hell’s Half Acre.

Their dedication transformed Jewel Cave from an obscure monument facing closure into the world’s third-longest cave system.

The story of how two volunteers saved a national treasure unfolds in the very chambers they discovered.

One Cave Trip Turned Into a 22-Year Adventure

In 1959, geologist Dwight Deal asked his friends Herb and Jan Conn to help explore a small South Dakota cave. The rock-climbing couple agreed to try caving “just once.”

Back then, Jewel Cave was a small national monument with only about 2 miles mapped. Some people even wondered if it should keep its monument status.

No one knew this single trip would start two decades of underground adventures that would save the cave from closing.

The Conns Caught Cave Fever Fast

That first trip hooked Jan and Herb completely. They started making regular trips into the cave, following air currents that pointed to hidden passages.

The cave “breathed” – air moved in or out based on outside air pressure. This breathing led the Conns to new openings.

Within months, they realized Jewel Cave was much bigger than anyone thought. The couple spent weekends and free time crawling through tight spots and mapping what they found.

Home Was a Stone Cabin Against a Cliff

The Conns bought 20 acres near Custer, South Dakota in 1949. They built a small stone house called “Conncave” against a cliff face in 1951.

Their simple home had no electricity or running water for the 60 years they lived there. Herb worked each summer hanging from ropes on Mount Rushmore, fixing cracks in the presidential faces to earn money.

Jan taught guitar and flute lessons. Their basic lifestyle let them focus on exploring the cave system.

Miles of New Passages Appeared in Just Two Years

By 1961, the Conns had mapped over 15 miles of unknown passages. Most new sections went beyond the original monument boundaries onto Forest Service land.

The cave grew from 2 miles to more than 15 miles in just 24 months of weekend trips. Park officials took notice as reports of the growing cave reached them.

The Conns kept detailed notes and maps of everything they found.

They Found the Path Tourists Walk Today

The Conns stumbled upon what would become the main tourist route in 1961. This section had tall narrow passages, huge rooms, and beautiful cave formations.

They squeezed through tight spots to find chambers with sparkling calcite crystals that gave the cave its name. Park officials got excited when they saw the Conns’ reports and photos of these amazing areas.

This find set up Jewel Cave to become a major tourist spot.

Government Agencies Swapped Land to Protect the Cave

The Forest Service and National Park Service traded land in 1965 to include the newly found cave sections within monument boundaries. Officials redrew the monument map based mostly on where the Conns had explored.

The Park Service began planning an elevator shaft and walkways to make remote cave areas open to visitors. Jewel Cave changed from a forgotten site to a priority thanks to the Conns’ volunteer work.

Tight Squeezes Got Funny Names

The Conns brought humor to their tough work by giving creative names to cave features. They called very narrow passages “Mighty Tight Street” and “Long Winded Passage.”

A huge room with great sound became “Carnegie Hall. ” Painful crawls got names like “Torture Chamber,” “Hell’s Half Acre,” and “The Other Half Acre.”

The “Black and Blue Grottoes” matched the bruises they often got while exploring. These fun names helped them remember spots in the growing maze.

Herb Explained Why the Cave “Breathes”

Herb wrote the first simple explanation of Jewel Cave’s breathing in 1966. He showed how changes in outside air pressure caused wind to blow in or out of cave entrances.

The Conns used this knowledge to find new passages – following the air often led to unexplored areas. They mapped with basic tools: compass, angle measurer, and tape.

Their careful approach turned casual exploring into serious science work. They wrote down every passage, room, and formation despite tough conditions.

Tourists Could Finally See the Conns’ Discoveries

The Park Service finished a 300-foot elevator shaft in 1972, making remote cave sections open to visitors.

Workers put in concrete walkways, metal stairs, and platforms along a half-mile loop through some of the most beautiful areas the Conns had found.

Electric lights showed off amazing formations that had been in darkness for millions of years.

The Scenic Tour opened to the public, letting regular folks see what only the Conns and a few other cavers had seen before.

Twenty-Two Years Underground Changed the Map

Between 1959 and 1979, the Conns made 700 trips into Jewel Cave. They gave more than 6,000 hours crawling, climbing, and mapping the underground maze.

The couple personally mapped 62.36 miles of cave passages.

Many trips lasted 12 hours or more in tough conditions – cold, wet, and often squeezing through tight spots that tested both their physical limits and fear of small spaces.

Their hard work changed what we know about the cave’s true size.

A Small Cave Became World Famous

The Conns’ work grew Jewel Cave from 2 miles to over 64 miles during their exploration years. The monument went from facing possible closure to becoming a major tourist attraction and scientific site.

Exploration continues today with the mapped length now exceeding 220 miles, making it the third-longest cave system on Earth. Jan and Herb’s discoveries form the foundation of modern Jewel Cave National Monument.

Their weekend hobby saved a natural wonder that might otherwise have been forgotten.

Visiting Jewel Cave National Monument, South Dakota

Jewel Cave National Monument at 11149 U.S. Hwy 16 in Custer lets you explore the cave system that Jan and Herb Conn mapped for 22 years.

Entry to the monument and visitor center is free, but cave tours cost $6-$45 and need advance reservations through recreation. gov. The popular Scenic Tour costs $16 for adults and follows the Conn’s original routes through calcite crystal formations.

All cave access requires guided tours only, and you’ll need closed-toe shoes since it stays 49°F underground year-round.

This article was created with AI assistance and human editing.

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