To locate the springs, look for the massive granite cliffs on either side of the river just upriver from Avalanche Ranch. This formation is called "Hell’s Gate," which coincidentally offers excellent ice climbing only a few hundred yards downriver. Just upstream from the cliffs, you’ll see a wide spot in the road and an open meadow across the river with a couple of decaying old buildings. The spring is just below the road grade at the river level. Make sure to keep an eye out for the herds of bighorn sheep that like to frequent the meadow just across the river from the springs. Quite often they will graze within 50 yards’ proximity of bathers in the springs.
The hot spring comes out of the bank, right into the river, where industrious bathers have stacked up rocks to make walls to form the pools, which are approximately 15-20 feet across, about two feet deep, and hold a dozen or more people. Just across the walls of the pools is the main channel of the Crystal River, which allows cold water to infiltrate the pools and cool the spring water. The hot springs are indeed very hot, hot enough to scald an unwary bather where the water enters the pools. If the pools are too hot just take out some of the rocks to let in more river water.
The springs were historically used by guests of Dan Penny, who owned a small hotel downstream on Avalanche Creek. Penny built a bathhouse with facilities for men and women. In the 1960’s, however, users began to bathe "au natural", provoking the ire of the nearby neighbors, who were very conservative. The neighbors began a campaign of destruction, bulldozing the bathhouse and even dumping boulders into the springs and covering them with tar. Even this did not dissuade the hardy bathers, who simply cleaned up whatever mess was made. Eventually a compromise was worked out with the help of Pitkin County officials, and the springs reverted to their natural state.
There is no caretaker of Penny Hot Springs, no restroom facilities, and no bathhouse. Consequently, bathers are asked to please clean up after themselves so the next person can also enjoy the springs. New users of the springs should be forewarned that the springs are "clothing optional" and that many users prefer to bathe in the nude. It is free and there are no amenities, so bring your own towels.