Montana’s Most Famous Caves Were Missed by America’s Greatest Explorers During Their 1805 Journey

Lewis and Clark Caverns, Montana

In 1805, the Corps of Discovery passed through what is now Montana, hunting for a route to the Pacific.

They mapped rivers, noted wildlife, and recorded their journey west. But they had no clue about the maze of caves right under their boots.

The Geologic Origins Of The Caverns

The limestone forming Lewis and Clark Caverns began as marine sediments 325-365 million years ago. Tiny ocean creatures with calcium-rich shells died and accumulated on an ancient seabed during the Mississippian period.

Pressure compacted these remains into thick layers of limestone. Geologists call this specific rock formation Madison Limestone, named after exposures along the Madison River.

The rock layers tilted during the Laramide Orogeny, a mountain-building event that created the Rocky Mountains 70 million years ago. This uplift positioned the limestone beds at angles that later facilitated cave formation.

How Water Shaped The Caverns

Water transformed all that solid limestone into hollow chambers through a process called dissolution. Rainwater absorbed carbon dioxide from the atmosphere and soil, creating a weak carbonic acid.

This slightly acidic water seeped through cracks in the tilted limestone beds. The water dissolved calcium carbonate along these pathways, gradually enlarging them into passageways.

The nearby Jefferson River originally carved channels into the rock. Over thousands of years, these water-carved passages expanded into the rooms and corridors that form the extensive cavern system today.

The Caverns’ Spectacular Formations

Mineral-rich water creates stunning cave decorations through slow precipitation. Stalactites hang from the ceiling where water droplets deposit dissolved minerals before falling.

Their counterparts, stalagmites, build upward from the cave floor as fallen drops evaporate and leave behind mineral residue. Some formations display banded patterns like “cave bacon” where mineral-laden water flows along the same surface.

Small nodules called “cave popcorn” form where water seeps through porous rock. The Paradise Room contains colorful formations, with mineral impurities creating ribbons of red, orange, and yellow through the white calcite.

The Corps of Discovery’s 1805 Camp

Meriwether Lewis and William Clark led their expedition within sight of the caverns on July 31, 1805. The Corps of Discovery paddled and pulled their boats up the Jefferson River that day.

Lewis wrote about mountains rising steeply on both sides of the river near their campsite along Antelope Creek. Physical exhaustion marked their progress.

Many men suffered injuries and fatigue after weeks of hauling heavy boats against the current. Lewis noted their “lame crew” needed rest after the strenuous journey upstream, and never got to discover the caverns themselves.

The Cave’s Official Discovery

Two local ranchers noticed steam rising from a mountainside while hunting in winter 1892. Tom Williams and Bert Pannell investigated the strange vapor and found a small opening in the rock.

Cold winter air caused the warm, moist cave air to condense into visible steam. This natural phenomenon revealed the hidden entrance to what would become Montana’s most famous cave system.

Williams returned six years later with proper equipment to explore further. He assembled a team of seven men who lowered themselves into the opening with ropes, illuminating the darkness with candles.

The Civilian Conservation Corps Transforms The Caverns

President Franklin Roosevelt’s New Deal program provided manpower to develop the park during the Great Depression. The Civilian Conservation Corps stationed 200 young men at Camp Cavern between 1935 and 1941.

CCC workers constructed the winding 3-mile access road up the mountainside. They built the distinctive Granite Keystone Bridge and carved stone steps into the cave floor that remain visible today.

In 1938, the corps blasted a 538-foot exit tunnel through solid rock. This engineering achievement created a one-way route through the caverns and allowed visitors to see the Paradise Room.

Visiting Lewis and Clark Caverns

The park sits 19 miles west of Three Forks or 17 miles east of Whitehall along Montana Highway 2. Visitors first encounter the main visitor center before driving to the Cave Visitor Center at road’s end.

Access to the caverns requires joining guided tours available May through September.

The park’s campground provides 40 campsites with various amenities. Three cabins and a tipi offer alternative accommodations, requiring advance reservations during peak season.

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