Tennessee

If Tennessee is your destination and soaking in hot springs is on your wish list, the only mineral bathhouse still in operation is in Red Boiling Springs. The 1880s saw a boom in the development of U.S. mineral springs resorts as summer getaways due to the popularity of places like Saratoga Springs in New York. But Red Boiling Spring reached its peak in the 1920s and 1930s, with the summer of 1936 bringing 14,000 people to this small town of approximately 800 residents at the time.

Five different types of mineral waters are found at Red Boiling Springs, with the springs mineralized through contact with exposed black shale, from which iron sulfate is dissolved into the waters. 

Three of the historic hotels are still in operation, with one built in 1924 that is listed on the National Register of Historic Places. It offers steam treatment, mineral tub baths and therapeutic massage.