The Hot Springs were used by both Shoshones and Arapahoes. Chief Washakie of the Shoshones ceeded the springs to the U.S. government as part of the treaty which established the Wind River Indian Reservation in 1896.
As part of the treaty, Chief Washakie stipulated that part of the hot springs remain free and available to everyone. A state bathouse in the Hot Springs State Park is free.
The hot springs produce 18,600,000 gallons of water every 24 hours. The temperature is 135 degrees fahrenheit.
Numerous dinosaur fossils from the Jurassic period have been recovered near Thermopolis.
Butch Cassidy was a frequent visitor in the Thermopolis area