The Pawcatuck River flows on the western border of Westerly and was once renowned for its own species of Westerly salmon, three of which are on the town's official seal. The river flows from inland, emptying into Little Narragansett Bay. It also serves as the boundary between Westerly and Pawcatuck, Connecticut. Three large salt ponds lie along the coast of Westerly which serve as shallow, reef-like pools whose outer walls form the long, white beaches for which the town is renowned. From west to east, these ponds are Maschaug Pond, Winnapaug Pond, and Quonochontaug Pond.