The Mystic Lakes, consisting of Upper Mystic Lake and Lower Mystic Lake, are closely linked bodies of water in the northwestern suburbs of Boston, Massachusetts. The lakes lie at an elevation of 1 meter above sea level, within the towns of Winchester, Arlington, and Medford, Massachusetts. Upper Mystic Lake is fed by the Aberjona River, and drains south, over the Mystic Dam, into Lower Mystic Lake, which in turn empties into the Mystic River and then Boston Harbor.