The Westport River in Westport consists of two elongated tidal bays (East and West Branches) which join to enter the Atlantic Ocean immediately east of the Rhode Island state line, about two miles west of Buzzards Bay. The East Branch has harbor facilities at its lower end, which is located immediately west of the Route 88 Bridge connecting Westport Point and Horseneck Beach. The harbor facilities are used mostly by recreational boaters.

Corps’ activity on the Westport River was completed in 1893 and consisted of removing obstructions in the East and West Branches to a depth of seven feet. In 1957, the state dredged two 14-foot-deep channels. The first was through the shoal area east of Halfmile Rock at the mouth of the river; the second was in the inner harbor west of Horseneck Point.