Ascutney Mill Dam, also known as the Windsor Upper Dam and the Mill Pond Dam, is an arch-gravity dam which is one of the oldest and among the earliest storage dams in the United States. It is made of cut granite and is located in Windsor, Vermont in Windsor County near the Connecticut River where it functioned as a source of hydropower and later, hydroelectric power. It is on the ASCE list of historic civil engineering landmarks since 1970 and is listed on the National Register of Historic Places (as Ascutney Mill Dam Historic District) since January 09, 2007.