Salt Sulphur Springs, near Union (Monroe County), was a popular health resort thanks to its mineral springs. The soothing spring waters were first discovered by European-Americans in 1805. By 1820, a stone bathhouse (still standing) and a large, expensive hotel had been built. People believed the water, a mix of salt and sulfur, could cure headaches and illnesses.

A notable visitor was U.S. Senator John C. Calhoun in 1844. The resort closed after the Civil War, during which both Union and Confederate armies used the property.

Later attempts to reopen the resort failed, and it closed for good in 1936. The historic stone hotel and buildings are still standing and are some of the largest groups of old stone buildings in the state. They were added to the National Register of Historic Places in 1985.