Middlesex Fells Reservation, often referred to simply as the Fells, is a public recreation area covering more than 2,200 acres in Malden, Medford, Melrose, Stoneham, and Winchester, Massachusetts. The state park surrounds two inactive reservoirs, Spot Pond and the Fells Reservoir, and the three active reservoirs (North, Middle, and South) supplying the town of Winchester.