Rockbridge State Nature Preserve is a protected area in Ohio’s Hocking Hills region, centered on the state’s largest known natural bridge, a sandstone span that gave the community of Rockbridge its name. Covering 182 acres along the Hocking River, the preserve was acquired by Ohio in 1978 and includes trail loops leading to the bridge and a nearby rock shelter on small tributaries near the river. The bridge, about 100 feet long, formed when water eroded softer layers beneath a cap of Mississippian Black Hand sandstone, leaving a suspended stone arch within the wooded river landscape.