Corps personnel from West Thompson Lake Project and the Connecticut State Department of Environmental Protection manage the natural resources at Mansfield Hollow Lake through a multiple-use approach. This approach to managing the 2,472 arces helps to meet present needs, and assures a diversity of resources for future generations to enjoy.

Mansfield Hollow Lake is and artificial lake created by the U.S. Army Corp of Engineers with the completion of the dam in 1952. Mansfield Hollow Dam impounds water from the Natchaug River, Fenton River and Mount Hope River. The lake drains into the Natchaug River, which then flows into the Shetucket River. Mansfield Hollow Dam is a flood damage reduction. These structures are designed to mitigate the hazard from flooding in downstream areas by impounding the large increases in runoff, which occur after precipitation events and control the release of this water.

Fish species observed in the lake included black crappie, pumpkinseed and bluegill sunfish, largemouth and smallmouth bass, yellow perch, brown bullhead, chain pickerel, white sucker, american eel, golden shiner, carp, and rainbow, brook and brown trout. Northern pike are also present, having been reintroduced to the lake in 1992. Fishing is good for largemouth bass and fair for smallmouth bass. The lake also provides good fishing for yellow perch and chain pickerel.

The bottom of the lake is made up of mostly sand and gravel. Fine sand, silt and organic matter, otherwise know as muck, make up most of the shallow areas. Aquatic vegetation is very sparse with only a few localized occurrences of submergent species. Two of which found in Mansfield Hollow Lake are Pondweed (Potamogenton) and waterweed (Eoldea).