For seven decades, Mount Clemens was internationally renowned as a mineral bath resort city. In 1865 the first well was sunk to obtain brine for salt production. Because of the high cost of separating the salt from the various other minerals and elements in the water, this process proved unprofitable. In the fall of 1870, however, a local mill operator, Dorr Kellogg, decided to bathe in the warm, sulfurous water. Impressed with its therapeutic qualities, city businessmen were inspired to invest in a bathhouse. Known as the Original Bath House, it was completed in 1873. At the turn of the century, nine bathhouses and over thirty hotels operated in Mount Clemens. Owing to the Great Depression and increasing use of internal medicine, this "spa era" ended by 1940.