Alligator Mound is an animal effigy mound in central Ohio, USA. Since Ephraim Squier and Edwin Davis first recorded and mapped it in 1848, many have speculated regarding its age and meaning, but with remarkably little systematic archaeological investigation. Many scholars have assumed the Hopewell culture (c. 100 BC-AD 400) built the mound, based principally on its proximity to the Newark Earthworks. The Hopewell culture, however, is not known to have built other effigy mounds. Limited excavations in 1999 revealed details of mound stratigraphy and recovered charcoal embedded in mound fill near the base of the mound. This charcoal yielded radiocarbon dates that average between AD 1170 and 1270, suggesting that the Late Prehistoric Fort Ancient culture (c. AD 1000-1550) made the mound. This result coincides with dates obtained for Serpent Mound in southern Ohio and suggests that the construction of effigy mounds in eastern North America was restricted to the Late Woodland and Late Prehistoric traditions. Ethnographic and ethnohistoric analogies suggest that the so-called 'Alligator' might actually represent the Underwater Panther and have served as a shrine for invoking the aid of supernatural powers.