The Columbia Encyclopedia, Sixth Edition. 2001-07.
Concord, river, United States
river, c.15 mi (24 km) long, NE Mass., a short tributary of the Merrimack, which it joins at Lowell. On Apr. 19, 1775, colonial militia fired some of the first shots of the American Revolution at the British over a bridge across the river at Concord, Mass. Henry David Thoreaus first book, A Week on the Concord and Merrimack Rivers (1849), records a boat trip with his brother.