Acadia Cliffs State Nature Preserve is a 112-acre protected area in southeastern Ohio, mostly in Washington County with a narrow extension into Athens County near the county line. Established in 1994, it is known for its sandstone cliffs and for preserving both natural and industrial history. The land takes its name from the Acadia Coal Company, a former owner. Within the forest are an old millstone quarry and abandoned millstones, reminders of earlier industry. The preserve was created in part to protect Bradley's spleenwort, Asplenium bradleyi, a state-listed plant species, and it is now managed by the Ohio Division of Nature Preserves.