The river was specified as the western boundary of the
Colony of Rhode Island and Providence Plantations in the original charter of 1663. It was formerly called the
Charles River between its source and the mouth of the
Wood River near
Bradford, Rhode Island. On April 20, 2006, an
Atlantic white-sided dolphin swam several miles up the river to
Westerly, Rhode Island, from
Little Narragansett Bay at the east end of Fishers Island Sound. It spent several hours at Westerly-Pawcatuck, near the bridge connecting Rhode Island and Connecticut, while several hundred spectators gathered to see it. According to the
Mystic Aquarium, the dolphin may have become separated from its pod at sea and had been searching for it. It was captured and taken later that night to the aquarium, where it died; it had become sick, underweight, and bruised during its journey upriver. The Pawcatuck River flooded during a fierce rainstorm in New England on March 29, 2010, with waters overflowing into both Westerly and Pawcatuck. Both towns evacuated low-lying areas, and some historic buildings were lost to flood damage along the course of the river, and its tributaries such as a 150-year-old general store in
North Stonington adjacent to the
Shunock River. ==Course==