 The river formed as the last glacier retreated from New England about 12,000 years ago, when glacial melting increased the sea level and low – lying coastal areas were flooded.Its river herring runs were an important source of food to both native and European inhabitants, and it served as the Hingham-Weymouth boundary as early as 1635.Various industries have used the river, including a steel mill, wool factory, and fertilizer factory.