The Sudbury Reservoir (2.02 square miles) is an emergency backup Boston metropolitan water reservoir in Massachusetts, located predominantly in Southborough and Marlborough, with small sections in Westborough and Framingham. It was created when the Sudbury Dam was constructed to impound the Stony Brook branch of the Sudbury River; no part of the reservoir lies in the town of Sudbury. Nearly 2,000 ha in the Sudbury Reservoir watershed are administered by the Massachusetts Department of Conservation and Recreation as a limited-access public recreation area.
