Merrimack River

The Merrimack River, formed by the confluence of the Pemigewasset River (left) and Winnipesaukee River (right) is shown on a map of the northeastern United States

The Merrimack River is a 110-mile-long (177-kilometer-long) river in the northeastern United States. It rises in central New Hampshire at the confluence of the Pemigewasset and Winnipesauke rivers, flows southward into Massachusetts, and then flows northeast, near the Massachusetts-New Hampshire border, until it empties into the Atlantic Ocean in Ipswich Bay.

The total watershed of the river is approximately 5,000 square miles (13,000 km²), covering much of southern New Hampshire and a portion of northeastern Massachusetts. On its banks are a number of small cities built to take advantage of water power in the 19th-century, when textile mills dominated New England economy: Concord (the state capital), Manchester, and Nashua in New Hampshire, and Lowell, Lawrence, and Haverhill in Massachusetts.

The river is probably best known for the early American literary classic A Week on the Concord and Merrimack River by Henry David Thoreau.

Among its tributaries is the Souhegan River, which extends west from the town of Merrimack, New Hampshire.

See also

• List of Massachusetts rivers
• List of New Hampshire rivers

• USGS Merrimack River drainage basin in Massachusetts
• Merrimack.org Merrimack River watershed in New Hampshire
• US Army Corps of Engineers Merrimack River basin reservoir and river level status