The Mystic River Reservation is a publicly owned nature preserve located along the Mystic River in eastern Massachusetts, United States. It forms part of the nearly 76-square-mile (200 km2) Mystic River watershed, and runs through the towns of Winchester, Arlington, Medford, Somerville, Everett, and Chelsea. The reservation includes four waterfront parks—Draw Seven Park in Somerville, Torbert MacDonald Park in Medford, the Mystic Lakes in Winchester, Arlington, and Medford, and Mary O'Malley Waterfront Park in Chelsea—and is open to the public year-round from dawn to dusk. The reservation is maintained by the Massachusetts Department of Conservation and Recreation.