Quabbin Reservoir is the largest body of water in the Commonwealth of Massachusetts and was built between 1930 and 1939. Today, along with the Wachusett Reservoir it is the main water source for Boston, about 65 miles east and 40 other communities in the greater Boston area. It is also, the water supply to three towns west of the reservoir and acts as backup supply for another three. It has a total capacity of 412 billion U.S. gallons and an area of 38.6 square kilometers. Quabbin water flows from the reservoir of the Wachusett Dam using the Quabbin Aqueduct. The Quabbin watershed is managed by the Massachusetts Department of Conservation and Recreation, while the water supply system is operated by the Water Resources Authority, Massachusetts. Winsor Dam and Goodnough Dike form the reservoir of the dams of the three branches of the Swift River. Quabbin Reservoir is part of the Chicopee River Basin.
Greater Boston began to overcome their local water supplies in the first half of the nineteenth century. Many potential sources of water were explored, including groundwater and rivers, but none was considered adequate in quantity and cleanliness to meet the needs of the rapidly growing city. After several years of controversy, the General Court of Massachusetts (the official name of the state Legislature) authorized the construction of the Cochituate Aqueduct to carry water to Boston from Lake Cochituate in Wayland and Natick, Massachusetts.
Due to the restrictions of the state, most areas around the reservoir are accessible only on foot, through fifty-five doors in the neighborhood. Few people in the deep woods, and has become a wildlife area. Bald eagles, moose, bear, foxes, bobcats and share the habitat. Large portions of Dana are on higher ground and their remains, especially the cellar holes and old green city (where a historical marker was placed stone) can be visited. Much of Prescott is also above the water, what is known as the Prescott Peninsula, but cannot be visited due to state restrictions, although there is an annual tour of the city by the Swift River Valley Historical Society . Some homes and existing roads that were once part of North Prescott (now New Salem), and there is a marker of town line just north of the gates, indicating the line of the ancient city of Prescott. Cellar holes were completed near the center of what was Prescott to accommodate the Five College Radio Astronomy Observatory operated by the University of Massachusetts Amherst.
Fishing is allowed in designated areas in the northern portion of the reservoir. There is a visitor center south of the dam and an observation tower, and Enfield Lookout. The area is accessible by car from the south using state Route 9. The reserve is a popular place for hiking and other outdoor activities. This area was part of the town of Enfield, which was annexed by Belchertown.