River, northeastern U.S. Rising in the White Mountains of central New Hampshire, it flows south into Massachusetts, then turns northeast and empties into the Atlantic Ocean after a total course of 110 mi (177 km).
The main cities along the river include Concord , Manchester , and Nashua, N.H., and Lowell , Lawrence, and Haverhill, Mass.; they used the river to power their textile mills in the 19th century.