One of the few effigy mounds in Ohio, Serpent Mound is the largest and finest serpent effigy in the United States. Nearly a quarter of a mile long, Serpent Mound apparently represents an uncoiling serpent. Serpent Mound lies on a plateau overlooking the valley of Brush Creek. Nearby conical mounds contained burials and implements characteristic of the prehistoric Adena people (800 BC-AD 100).

Many questions surround the meaning of Serpent Mound, but there is little doubt it symbolized some religious or mythical principle for its builders. The museum contains exhibits on the mound and the geology of the surrounding area.