Hueston Woods State Park in southwestern Ohio combines Acton Lake, protected woodland, fossil-rich geology, and extensive recreation within nearly 3,000 acres. Ohio acquired the land in 1941 and first used it as a prison camp before opening the park in 1957. In 1956, Four Mile Creek was dammed to form the 625-acre reservoir named for legislator Clyde Acton. The park’s beech-maple climax forest became a National Natural Landmark in 1967, and its limestone and shale preserve abundant fossils from an ancient shallow sea. Historic and built features include the Doty Homestead and the Hueston Woods Covered Bridge, alongside boating, camping, trails, and other outdoor activities.