Merrimack River

The Merrimack River (or Merrimac River, an occasional earlier spelling[1]) is a 117-mile-long (188 km) river[2] in the northeastern United States. It rises at the confluence of the Pemigewasset and Winnipesaukee rivers in Franklin, New Hampshire,[3] flows southward into Massachusetts, and then flows northeast until it empties into the Gulf of Maine at Newburyport. From Pawtucket Falls in Lowell, Massachusetts, onward, the Massachusetts–New Hampshire border is roughly calculated as the line three miles north of the river.

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Merrimack River Merrimac River
Mouth of Merrimack River in Newburyport, Massachusetts, in 2021
The Merrimack River and its major tributaries
Location
Country	United States
State	New Hampshire Massachusetts
Region	New England
Cities	Concord, NH, Manchester, NH, Nashua, NH, Lowell, MA, Lawrence, MA, Haverhill, MA, Newburyport, MA
Physical characteristics
Source	Pemigewasset River-Winnipesaukee River juncture
• location	Franklin, Merrimack County, New Hampshire
• coordinates	43°26′11″N 71°38′53″W
• elevation	280 ft (85 m)
Mouth	Gulf of Maine
• location	Newburyport, Essex County, Massachusetts
• coordinates	42°49′10″N 70°48′43″W
• elevation	0 ft (0 m)
Length	117 mi (188 km)
Basin size	5,010 sq mi (13,000 km2)
Discharge
• location	Newburyport, Massachusetts
• average	7,562 cu ft/s (214.1 m3/s)
Basin features
Tributaries
• left	Soucook River, Suncook River, Beaver Brook, Powwow River
• right	Contoocook River, Piscataquog River, Souhegan River, Nashua River, Concord River, Shawsheen River

v t e Merrimack River
Legend
Franklin US 4 Boscawen Contoocook River I-93 I-393 NH 9 Concord US 3 Turkey River Soucook River Suncook River Hooksett I-93 Black Brook Amoskeag Falls Manchester Pan Am Railways Piscataquog River I-293 Pan Am Railways Cohas Brook Souhegan River Pennichuck Brook Nashua River NH 111 Nashua Salmon Brook Circumferential Highway enters Massachusetts Route 113 Tyngsborough Stony Brook Pawtucket Falls Mammoth Road Lowell Beaver Brook Concord River I-93 Great Stone Dam Route 28 Lawrence Spicket River I-495 Shawsheen River I-495 I-495 Haverhill Haverhill Line Little River Route 125 Route 97 West Newbury Artichoke River Maudslay State Park Powwow River I-95 Newburyport US 1 Salisbury Beach

The Merrimack is an important regional focus in both New Hampshire and Massachusetts. The central-southern part of New Hampshire and most of northeast Massachusetts is known as the Merrimack Valley.

Several U.S. naval ships have been named USS Merrimack and USS Merrimac in honor of this river. The river is perhaps best known for the early American literary classic A Week on the Concord and Merrimack Rivers by Henry David Thoreau.