So, you haven’t heard of Dempsey, largely because it wasn’t called that for long. Dempsey was in southeastern Idaho, where Bob Dempsey, a trapper, had his camp for about 10 years from 1851 to 1861. He moved to the Montana gold fields after that and dropped off the map. The town named after him got a post office in 1895, but the name Dempsey disappeared in 1915, when they started calling the place Lava Hot Springs, which is more reflective of the major draw to the town.
The hot springs were deeded to the State of Idaho in 1902. In 1913, the hot springs site became a state park, and the state built a natatorium there in 1918. In 1967 management of the site was taken over by the newly formed Lava Hot Springs Foundation, a group appointed by the governor to run the place. That foundation is still in existence today, running a large complex of water features.
The pools at Lava Hot Springs are from 102 to 112 degrees. Their Olympic-sized outdoor pool has diving boards, high and low diving platforms, and corkscrew waterslides. Next to the pool is the big waterslide that comes swooping in right across the main road into town.
Located about 45 minutes south of Pocatello not far off I-15, Lava Hot Springs is a major draw for Utah recreationists.