Lava Hot Springs City
Lava Hot Springs City Hall is located at 115 Elm Street, Lava Hot Springs, ID 83246; phone: 208-776-5820.
Lava Hot Springs was platted by John Hall in 1911. It was incorporated in 1915.
City as Described in the 1930s 
Lava Hot Springs is one of the most phenomenal spots in the State, but Idahoans have been too busy taking the rough edges off an empire to give it much interest. Natatoriums, it is true, have been established there, two by the State and one by the town; and there is a fully equipped sanitarium. This town, situated on the lovely Portneuf River at the base of great cliffs, has waters which, in both volume and therapeutic value, are said to be among the most remarkable springs known. For centuries the Indians paid tribute here to the Great Spirit for the curative properties of these hot springs and set this spot aside as neutral ground to be shared in peace by all tribes. The daily flow from the hot springs here, each with a different mineral content, is 6,711,000 gallons. The springs have an average of 962.33 parts of mineral content per million. It is locally claimed that the mineral content of these springs is higher than that of any other hot spring in the North American Continent or in Europe.
Both the State and City natatoriums have large indoor pools, the better one of which is the first. The State also has an outdoor pool, called the Mud Bath, which is amazingly characterized by the varying degrees in the temperature of its waters. It is not a large pool, but a swimmer can stroke from almost cold water into hot water and through various degrees of cold and warmth between the two extremes. This circumstance owes to the fact that thirty springs of varying temperature pour into this pool. Three springs, the Ha-Wah-Na, the Sulphur, and the Iron, have a total dissolved content of minerals of more than nine hundred and fourteen hundred respectively. Just below the balcony of the Riverside Inn runs the clear cold water of the Portneuf River with hot springs steaming almost at its edge.
Against the town to the south is a great mountain that is almost a solid pile of un-quarried building stone, which because of its strength and lightness has been characterized by engineers as one of the best yet found. It can be seen in two cabins across the river from the Mud Bath, and in cigarette trays in the Inn. Interesting, too, are other rock formations of Paleozoic limestones, shales, sandstones, and quartzites. Upon the river within the radius of a mile are fifty small waterfalls; and the smoke holes of old volcanoes are within hiking distance. The canyons and glens offer camping retreats, and fishing in the river is good for a stream so accessible.