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New Hampshire Department of Environmental Services

Designated Rivers
The Lower Merrimack River Report to the General Court

Lower Merrimack River MapThe Merrimack River is the second largest river in New England, draining a total area of 5,014 square miles extending from the White Mountain region of New Hampshire to east-central Massachusetts. The river, which bisects the lower third of New Hampshire, begins at the confluence of the Pemigewasset and Winnipesaukee Rivers in Franklin. It flows for 116 miles before entering the Atlantic Ocean in Newburyport, Massachusetts.

A segment of the river, known as the Lower Merrimack, is one of two on the river designated under the NH Rivers Management and Protection Program in June 1990 protecting nearly 45 river miles. The segment begins at the Merrimack-Bedford town line and flows for approximately 15 miles through the communities of Merrimack, Litchfield, Hudson, and Nashua before entering Massachusetts.

The Lower Merrimack River flows through a region of rapid population growth and development that is heavily influenced by the Boston metropolitan area. Notably, it provides drinking water to the city of Nashua and surrounding towns as well as to downstream communities in Massachusetts, including the cities of Lowell and Lawrence.


The Merrimack River played a pivotal role in the settlement and subsequent development of the region. Native American sites, cellar holes, cemeteries and the remains of a canal navigation system are included among the prehistoric and historic sites which offer additional historic knowledge of the river and its corridor. Of particular interest are the Naticook Islands, just downstream of the Depot Street public access in Merrimack, which are said to have been the summer home of the great Native American Chief Passaconoway. Another historical highlight of the area are the locks at Cromwells Falls, renowned by The American Canal Society as the best remaining specimen of the Merrimack River Navigation System. In Litchfield, two archaeological sites have been deemed eligible for listing on the National Register of Historic Places: the Thebodeau site north of Chase Brook and the Danforth Archaeological District in south Litchfield.

Wildlife and Plant Resources

Though located in a region of rapid land development, the Lower Merrimack River is a safe haven of critical habitat for a variety of plant and animal species, including the federally-listed threatened bald eagle. The river corridor provides the necessary elements of eagle wintering habitat: perch or roost sites and open waters for fishing. This stretch of secluded, quiet water is a valuable source of wildlife habitat. Perch sites -- large open branched trees -- on the river's bank provide the eagles with good viewing areas from which to locate food. At night, the eagles move to more sheltered inland areas, usually conifer stands, that offer protection from the wind and cold temperatures. The Audubon Society of New Hampshire, which records eagle sightings in New Hampshire, has found that the level of winter eagle activity on the Merrimack River is second only to that on Great Bay, a tidal estuary system on New Hampshire's coast. As one of New England's major north-south running rivers, the Lower Merrimack River also serves as a key migratory route for waterfowl and songbirds.

The New Hampshire Natural Heritage Inventory has identified several state-listed threatened plant species within the river corridor, including the wild lupine. In addition, the river corridor supports two exemplary natural communities: Southern New England lake sediment/river terrace forest and Northern New England level bog. One state threatened reptile, the eastern hognose snake, is also believed to live in the river corridor.


Current boating activities on the Lower Merrimack River include canoeing, kayaking, rowing and power boating. The river provides both quickwater and flatwater experiences for canoeists and kayakers and is one of the largest surface water bodies in the region for power boating. The Merrimack River Watershed Council sponsors a variety of canoe trips on the Merrimack and its tributaries throughout the spring, summer and fall for beginner and intermediate paddlers.

Just north of the designated segment, boaters can access the river at three public access sites in Manchester. Kayakers and whitewater canoeists may be lured to Arms Park, a city recreation area, located off North Commercial Street, as a whitewater slalom course exists at the site. In Merrimack, there is access at Depot Street (off Exit 12 on the Everett Turnpike) at Reeds Ferry. This is a suitable put-in for motorboats, as the river slows from the rocky rapids upstream. At the north end of Greely Park in Nashua, there is a paved ramp which also allows access to boaters.


Efforts are underway to obtain easements for a hiking trail that would become part of the New Hampshire Heritage Trail, stretching from the Massachusetts border, north along the Merrimack, Pemigewasset and Connecticut Rivers, to the Canadian border. Several trail sections are complete along this part of the river. In Bedford, the trail begins at Moore's Crossing Road and follows the river north for one mile. Another section of the trail begins at Merrill Park off Maple Avenue in Hudson, and continues along the river south into Massachusetts. Trail users also have the option to travel west into Nashua to explore that city's historic district and a section of the Nashua River, a major tributary to the Merrimack.


Anadromous fish species are beginning to return to the Lower Merrimack River as the result of a cooperative state-federal restoration program that began in 1969. New and improved fish passage facilities and on-going research efforts are directed toward the return of the native Atlantic salmon to waters as far north as the Pemigewasset River. The completion of a fish passage facility at the Pawtucket Dam in 1986 has allowed American shad to move upstream to Manchester after more than a century's absence. Important game species sought by anglers on the Lower Merrimack River include small and large mouth bass as well as rainbow and brook trout which are stocked by the New Hampshire Fish and Game Department. Access can be gained to the river at various points in Nashua, Merrimack and Manchester.

NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
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