Merrimack River - History and Details

History and Details

Prior to glaciation, the Merrimack continued its southward course far beyond the present day New Hampshire-Massachusetts border to enter the Atlantic Ocean near Boston. Upon the glacier's retreat, debris deposited north of Boston filled the lower Merrimack Valley, redirecting the river into its current northeast bend at Lowell. The Neville archaeological site is located along the river's banks in New Hampshire.

The total watershed of the river is approximately 4,700 square miles (12,200 km2), covering much of southern New Hampshire and a portion of northeastern Massachusetts. On its banks are a number of cities built to take advantage of water power in the 19th century, when textile mills dominated the New England economy: Concord, Manchester, and Nashua in New Hampshire, and Lowell, Lawrence, and Haverhill in Massachusetts. At the mouth of the river is the small city of Newburyport. Prior to the construction of the Middlesex Canal, Newburyport was an important shipbuilding city, in a location to receive New Hampshire timber that had been floated downriver. The river enters Massachusetts at the town of Tyngsborough and from there, winds past or through Chelmsford, Lowell, Dracut, Tewksbury, Andover, Methuen, Lawrence, North Andover, Haverhill, Groveland, West Newbury, Merrimac, Amesbury, Newburyport, and Salisbury.

The river is perhaps best known for the early American literary classic A Week on the Concord and Merrimack River by Henry David Thoreau. Among its tributaries are the Souhegan River, which extends west from the town of Merrimack, New Hampshire; the Nashua River, which flows north into the city of Nashua; the Concord River, which flows north from Concord, Massachusetts to Lowell; and the Shawsheen River, which after also flowing north, joins the Merrimack at Lawrence.