St. Mary's River State Park in St. Mary's County, Maryland, consists of two separate sites: one focused on the 250-acre St. Mary's Lake and another spanning 2,200 largely undeveloped acres. Managed by the Maryland Department of Natural Resources, the park took shape through land acquisitions from 1968 to 1983, with the first site assembled between 1968 and 1974 and the lake built in 1975. The park now supports fishing, non-motorized boating, canoeing, picnicking, and hunting. Its 7.5-mile trail around St. Mary's Lake is a central attraction for hikers, horseback riders, and mountain bikers.