Minnetonka Cave
St. Charles Canyon Road
St. Charles, ID
A cool, half-mile limestone cave of stalactites and banded travertine high above Bear Lake, found by a hunter chasing a fallen grouse in 1906.
Minnetonka Cave is the largest limestone show cave in Idaho, a half-mile of dripping chambers hidden in the mountains high above Bear Lake. Guided tours lead down through nine rooms decorated with stalactites, stalagmites, and ribbons of banded travertine, all of it built up drop by drop over an immense span of time.
The cave was found by accident. In 1906 a hunter named Edward Arnell shot a grouse that tumbled over a ledge, and when he scrambled after it he felt cold air pouring out of the mountainside. That draft led to this underground world, which was developed in the 1930s into the lighted, stair-stepped show cave visitors tour today. The name Minnetonka is often glossed as falling water.
What Guests Love
- A cool underground walk through nine chambers of stalactites, stalagmites, and banded travertine
- The steady chill of the cave, a welcome escape on a hot Bear Lake summer day
- The story of its accidental discovery by a hunter in 1906
- Ranger-guided tours that bring the formations and the cave's history to life
Worth Knowing
- The cave is open for guided tours only in the warmer months, roughly from mid-June through early September
- It stays cold inside year round, so bring a jacket even in summer
- The tour involves a lot of stairs and a steady descent and climb, so it is a workout on the way out
- It is a summer bat roost, so tours follow rules that protect the animals and their habitat
Details
St. Charles, ID
Learn about Minnetonka Cave
How the cave formed
The cave was dissolved out of ancient limestone, rock originally laid down as sediment on the floor of a long-vanished sea. Geologists believe it began as a stream that once fed into St. Charles Canyon, slowly eating passages through the soluble stone.
Once the passages drained, water seeping through from above began the slow work of decoration, depositing mineral drop by drop to grow the stalactites hanging from the ceilings, the stalagmites rising from the floors, and the flowing curtains of travertine. It is patient, water-driven artistry measured in thousands upon thousands of years.
The 1906 discovery
The tale of Edward Arnell and his grouse is the kind of origin story that sounds too good to be true but is well documented locally. A bird fell over a ledge, a hunter went to fetch it, and a rush of cold air betrayed the hidden opening.
In the 1930s the cave was developed as a public attraction, with well over a thousand feet of illuminated trail, handrails, and stairs installed so visitors could explore safely. It has drawn generations of Bear Lake travelers underground ever since.
Life in the dark
Like many limestone caves, Minnetonka is a sanctuary for bats, which roost here in the warmer months, and tours are managed to protect them and the fragile cave environment.
Above ground, St. Charles Canyon is forested high country, home to deer, moose, and mountain birds, and the canyon road up to the cave passes creeks and campgrounds worth a stop.
When to visit
The cave is a summer destination, since tours run only from roughly mid-June to early September and the access road is closed by snow in the colder months. That timing pairs perfectly with a Bear Lake summer.
Whatever the weather outside, dress for cold underground, and be ready for the stairs, which are the reason many visitors say the climb back to daylight is the real exercise.
Closest Boutels
The closest Boutel™ stays, so you can turn this stop into an overnight. Each is an independently owned, editorially selected place to stay.
Things to Do Near St. Charles
Bear Lake
About 10 miles south
The turquoise Caribbean of the Rockies, a big high-altitude lake famous for its color, beaches, and raspberries.
Bear Lake National Wildlife Refuge
About 15 miles southeast
A marshy refuge at the north end of the lake, a haven for nesting waterbirds and migrating flocks.
St. Charles
At the canyon mouth
The small Idaho village at the foot of the canyon, birthplace of the Wild West showman associated with Bear Lake's frontier lore.