Merrimack

River in northeastern USA, rising in the White Mountains of New Hampshire and flowing through northern Massachusetts to the Atlantic Ocean; length 177 km/110 mi. With the river's many waterfalls and rapids supplying hydroelectric power for manufacturing, the Merrimack valley became one of the earliest industrial regions in North America, with many mill towns, including Manchester, Nashua, and Concord in New Hampshire, and Lawrence and Lowell in Massachusetts. The river valley is now a tourist route.

The Merrimack River Watershed Council aims to maintain and improve the health of the river for communities and the ecosystem.