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 body of water in Massachusetts. According to the Massachusetts Department of Conservation and Recreation the Winsor Dam is one of the largest dams in the Eastern U.S. The Winsor Dam is part of the Chicopee River Watershed. The Winsor Dam was named for Frank E. Winsor, its chief engineer.

Winsor Dam bridge
Coordinates	42°16′59″N 72°20′36″W / 42.2831°N 72.3433°W / 42.2831; -72.3433
Carries	Winsor Dam Road
Characteristics
Width	Two lanes
Clearance above	Unrestricted
Statistics
Daily traffic	Closed
Location

The dam has the following characteristics:

• Length: 2640 ft (805 m)
• Top width: 35 ft (10.7 m)
• Max. bottom width: 1100 ft (335 m)
• Height above river: 170 ft (52 m)
• Height above bedrock: 295 ft (90 m)
• Amount of earth fill: 4 million cubic yards (3,000,000 m).

• Technical information
• Information about the Quabbin Reservoir
• Court order and statement of facts about MWRA facilities