Weymouth Fore River is a small bay or estuary in eastern Massachusetts and is part of the Massachusetts Bay watershed.
The headwater of Weymouth Fore River is formed by the confluence of the Monatiquot River and Smelt Brook in the Weymouth Landing area of Braintree. From Weymouth Landing, the tidal river marks the boundary between Braintree and Weymouth, flowing NE for 0.5 miles (0.80 km) and then N for 0.5 miles (0.80 km) before widening considerably and turning WNW for 0.7 miles (1.1 km). At this point the river's western shore is now in Quincy at the south end of the former Fore River Shipyard. Here the river turns NNE for 1.0 mile (1.6 km) as it passes through a heavily industrialized area around the former shipyard and is crossed by the Fore River Bridge, a temporary lift bridge which carries Massachusetts Route 3A between Quincy and Weymouth. A quarter mile beyond the bridge Weymouth Fore River is joined by Town River at Germantown, gradually widening to nearly 1 mile (1.6 km) as it travels the final 2.0 miles (3.2 km) NE before ending as it enters Hingham Bay.
Recreation along Weymouth Fore River includes Smith Beach/Watson Park in East Braintree along the NW shore near Weymouth Landing at the river's south end and Wessagussett Beach on the SE shore in North Weymouth before the river enters Hingham Bay. The United States Naval Shipbuilding Museum located in Quincy Point at the west end of the Fore River Bridge features the USS Salem (CA-139), a preserved heavy cruiser which is open to the public.