Mansfield Hollow Lake

Largest tributaries

Mansfield Hollow Lake is a reservoir resting on the border of Windham County and Tolland County, Connecticut. The reservoir provides drinking water for Willimantic and helps control flooding in Thames River watershed. It was created by the Mansfield Hollow Dam and is entirely contained within Mansfield Hollow State Park and the Mansfield Hollow Wildlife Area. Designed and constructed by the United States Army Corps of Engineers, the dam substantially reduces flooding along the Quinebaug, Shetucket, and Thames rivers. Construction of the project began in 1949 with completion in 1952 at a cost of US$6.5 million. The Mansfield Hollow reservoir is located within the Shetucket River Watershed and is part of the Thames River Basin.