The Winsor Dam and the Goodnough Dike impound the waters of the Swift River and the Ware River Diversion forming the Quabbin Reservoir, the largest water body in Massachusetts. According to the Massachusetts Department of Conservation and Recreation the Winsor Dam is one of the largest dams in the U.S. east. The Winsor Dam is part of the Chicopee River Watershed. The Winsor Dam was named for Frank E.