Lake Francis is a reservoir on the Connecticut River in northern New Hampshire, United States. The lake is located in Coos County, east of the village of Pittsburg and along the boundary between the towns of Pittsburg and Clarksville. The lake is impounded by Murphy Dam, built in 1940 as a flood control project. The 117-foot (36 m) earthen dam is owned by the Water Division of the state's Department of Environmental Services, and is operated by TC Energy.