Both the Sioux and Cheyenne claimed possession of this natural river of warm water springs that flows here. Local legend tells of a fierce battle that raged on the east summit above the springs and river (now called Battle Mountain), with the Sioux emerging victorious. 

Years later, in 1876, Colonel W.J. Thornby arrived at the present site of Hot Springs and discovered the source of the warm creek. Near the big spring where the Plunge was later built, he lopped off the top of a cedar sapling, blazed the trunk, and wrote with lead pencil: "This is my spring. W.J. Thornby." In 1881 the spring was held by Joe Brimdschmidt. He traded the spring to Joe Petty for a horse valued at thirty-five dollars! Petty then sold the Plunge Springs to Dr. Stewart who filed on the surrounding land.