The Homestead Caldera, known locally as "The Crater", is a natural hot spring hidden inside a 55-foot tall, beehive-shaped limestone rock in Midway, Utah. Directly above the spring is a large natural opening, which was originally the only entrance to the crater. Those who wished to soak in the mineral-rich warm waters had to rappel through the hole at the top. It was only in 1996, that a tunnel was blasted through the base of the rock dome allowing visitors easy access.
The Crater dome was formed about 10,000 years ago by the deposition of minerals, mainly calcium, that produces a white, porous lava-like rock that is very common in the Midway area. Studies suggest that rain and snow melt in the nearby Wasatch Mountains percolated into the ground, descended along cracks and fractures to depths of one to two miles to get heated by the earth’s interior. The heated water returned to the surface and deposited that material as travertine.
Today, the mineral-rich water is piped out of the crater so that the dome no longer grows. Because the water is constantly changing, as it is piped out, the temperature remains at a steady 96 degrees Fahrenheit (35.5 degrees Celsius) and visibility is astounding. Even from the bottom, divers can see clouds in the sky through the hole at the top.
Now part of the Homestead Resort, the Caldera is the largest mineral dome in the area. It is approximately 55 feet high and 400 feet across on the outside. The inside chamber is 85 feet across. The water in the crater is pretty deep too —about 65 feet. It is currently the only warm-water scuba diving site in the continental United States.
