Indian Mound Reserve near Cedarville, Ohio, preserves a steep Massies Creek canyon and two major prehistoric earthwork sites, the Williamson Mound and the Pollock Works. Long known locally as the Cliffs and used for picnics, the area later gained formal protection as an important archaeological landscape. The Williamson Mound, now attributed to the Adena culture and dating to the final centuries before Christ, is a large burial mound that may preserve evidence of changing burial practices over time. The Pollock Works, now understood as a Hopewell construction begun in the first century AD, combined real defenses with ceremonial purposes. Together these sites make the reserve one of Greene County’s most significant historic places.