Middlesex Fells Reservation, often referred to simply as the Fells, is a public recreation area covering more than 2,200 acres (890 ha) in Malden, Medford, Melrose, Stoneham, and Winchester, Massachusetts, United States. The state park surrounds two inactive reservoirs, Spot Pond and the Fells Reservoir, and the three active reservoirs that are part of the water supply system for the town of Winchester. Spot Pond and the Fells Reservoir are part of the Wachusett water system, one of six primary water systems that feed metropolitan Boston's waterworks. The park is managed by the Massachusetts Department of Conservation and Recreation and is part of the Metropolitan Park System of Greater Boston.