In Millard County, Utah, there is a natural cave that rivals man-made architectural wonders. This limestone and feldspar cavern was once filled by Lake Bonneville. Since 1956, the Bates family has curated the attraction for the Federal government and offers guided tours from their nearby ranch.
The story goes that the father of the family was out looking for his sheep in the hills and chanced upon a narrow opening in the rock. He uncovered a massive cavern that has, for years, sparked archaeological and geological debates as experts continue to study the cave. From prehistoric creatures to geological mysteries, visitors leave with a story that’s millennia in the making.
Minerals found in the cave range from common to rare. One mineral found in the cave, calcite iceland spar—also called “optical calcite”—is revered for its crystal clarity. Historically, it was used for various optical instruments, including the top secret Norden Bombsight of World War II.
You can get an authentic ranch-lodging experience in the Bates’ custom cabins, which offer a respite from the Utah sun in a shaded grove of crabapples and grand trees. This land has been in their family since pioneers settled the land.
Several miles from the ranch cabins is Gandy Warm Springs, which is publicly accessible via a gravel road. Clean, clear, and constantly 81 degrees, this oasis is the perfect place for a swim on a hot day or a soak in the cool evening twilight. Reeds and brush make the spring semi-private from the otherwise wide-open valley.
Know Before You Go
Key to this pristine place is its remoteness so always bring water! Your cell service may be non-existent in certain areas.
Flashlights and headlamps are recommended for the cave tour. Tours must be scheduled ahead of time. The ranch and cave tours operate on Mountain Standard Time. This is a working ranch so please show courtesy when canceling or delaying a tour appointment. Comfortable hiking shoes are strongly encouraged.
Lastly, the spring is fed from an (unexplored) cave; please avoid swimming into this cave for your own safety.