river in southwestern New England, rising in the Berkshire Hills, near Pittsfield, Mass., U.S. It flows southward for 148 miles (238 km) through Massachusetts past Pittsfield, Lee, and Great Barrington; and then through Connecticut past New Milford, Derby, and Shelton to enter Long Island Sound, 4 miles (6 km) east of Bridgeport. Several hydroelectric plants utilize the river's drop of 959 feet (292 m) in the first 119 miles (191 km) to Derby. Below Derby the river is tidal for about 12 miles (19 km). Lake Zoar is impounded in the river in Paugussett State Forest. The name Housatonic is supposedly derived from the Mohican (Mahican) Indian word for “place beyond the mountain.”