Weymouth Back River in Weymouth and Hingham is located between Hingham Harbor on the east and Weymouth Fore River on the west, about 10 miles south of Boston. A local yacht club and several marinas are the river’s primary users.

Initial work on the Weymouth Back River, completed in 1912, consisted of a 12-foot-deep channel 200 feet wide extending from the river mouth at Weymouth Lower Neck to the wharf of a former fertilizer company, about one mile upstream. The present project, completed in 1943, consists of a 15-foot-deep channel extending from Weymouth Lower Neck, through the bar at the river mouth, to the wharf of the former fertilizer company. The one-mile-long channel is initially 250 feet wide at the mouth, then narrows to 200 feet wide. The project also includes a 400-foot-long turning basin, 350 feet wide, in the vicinity of the wharf.