Medicine Rock originally stood on a hillside just south of the Little Cheyenne River, about 125 feet from the shore and about 1.15 miles northeast along a meandering shoreline from where the road now reaches the Oahe Reservoir, but the site is normally under 50 feet of water. The flat limestone, about 12 by 20, was regarded as sacred by the Sioux Indians and probably by generations before them because of a man's footprints and other tracks on it. First observed by the Atkinson-O’Fallon Peace Treaty expedition of 1823, it was later commented on by river travelers. During Sully's expedition of 1863, Captain John Fielner made a solo trip to see the rock and was killed by Indians who coveted his horse and gear. Sully pursued them, captured and beheaded them, and placed their heads on high poles as a warning to Indians who killed without cause. About a mile from the water's edge lies Old Forest City, Potter County's first county seat, also now underwater under about 90 feet of water.