The Naugatuck River is a  river in the US state of Connecticut. It carves out the Naugatuck River Valley. Its waters flow from north to south through western Connecticut to the Housatonic River at Derby, Connecticut and thence to Long Island Sound. The Plume and Atwood Dam in Thomaston, completed in 1960 following the Great Flood of 1955, creates a reservoir on the river and is the last barrier to salmon and trout migrating up from the sea.