The North River is a river, approximately 12 miles (19 km) long, in eastern Massachusetts, the United States. It is primarily a tidal river, formed by the confluence of the Indian Head River and Herring Brook. The North River forms the boundary between the towns of Norwell , Pembroke, Massachusetts, Hanover, Massachusetts and downstream, the boundary between Scituate and Marshfield. The river flows into Massachusetts Bay at New Inlet, where it also converges with the mouth of the South River. The North River area is also known as the "Irish Riviera" due to the large Irish American population that migrated during the 19th century.