Pawcatuck is a village and census-designated place in the town of Stonington which is located in New London County, Connecticut. The population was 5,624 at the 2010 census. It is located across the Pawcatuck River from Downtown Westerly, Rhode Island. The Mechanic Street Historic District of Pawcatuck is listed on the National Register of Historic Places and includes sites of shipbuilding, mills, and worker housing in a 147-acre area.