Skip to Navigation

The Great Marsh

Site Facts

Country, State, Province/Region:

United States, Massachusetts

Relative Location:

Approximately 35 miles northeast of Boston, including the towns of Gloucester, Essex, Ipswich, Rowley, Newbury, Newburyport, and Salisbury


42º 44' N, 70º 48' W



Basis for Designation:

The Great Marsh is one of the most important coastal ecosystems in northeastern North America, and is the largest contiguous salt marsh north of Long Island, New York. The area supports more than 67,000 shorebirds representing 30 species. The Great Marsh is particularly valuable to shorebirds during the fall migration.


25,000 acres



Site Owner/Steward:

A partnership of federal, state, municipal, non-governmental non-profit organizations, and private entities. The largest landowners within the Great Marsh are: Parker River National Wildlife Refuge (4,662 acres), The Trustees of Reservations (1,300 acres) and Essex County Greenbelt Association (1,809 acres), which owns an additional 1,144 acres of conservation easement land.

Site Partners:

Parker River National Wildlife Refuge, Massachusetts Audubon Society, The Trustees of Reservations, Essex County Greenbelt Association, Parker River Clean Water Association, Eight Town and the Bay Committee, Friends of Parker River Refuge, and Essex National Heritage Commission.

Human Population within 100 km:

> 3.5 million


Frank Drauszewski
Deputy Refuge Manager, Parker River NWR


The Great Marsh is the largest salt marsh in New England and includes over 20,000 acres of marsh, barrier beach, tidal river, estuary, mudflat, and upland islands extending across the Massachusetts North Shore, from Gloucester to Salisbury. In recognition of these extraordinary resources, a portion of this area was designated by the state in 1979 as the Parker River/Essex Bay Area of Critical Environmental Concern. The Great Marsh is an internationally recognized Important Bird Area (IBA) because it contributes to the preservation of many breeding and migratory birds. With its network of waterways, beaches, parks, and wildlife refuges, the Great Marsh is an outstanding destination to enjoy boating, fishing, birdwatching, hiking, and beach activities throughout the cities and towns of Gloucester, Essex, Ipswich, Rowley, Newbury, Newburyport, and Salisbury. 

Ecology and Conservation

The Great Marsh’s complex of salt marsh grasslands, tidal creeks, and estuaries makes it an incredibly habitat-rich place. The largest salt marsh in New England, it contains an astonishing diversity of plants and animals.

Conservation Status and Special Resources
A comprehensive management approach is in practice within the Great Marsh. The entire area is very fortunate to be afforded protection under the State’s designation as an Area of Critical Environmental Concern (ACEC).  This designation carries a high level of concern and protection enforced by the State. Additionally, the U.S. Fish and Wildlife Service (USFWS) manages Parker River National Wildlife Refuge (NWR) primarily for the benefit of wildlife, with particular emphasis on migratory birds. The non-profit organizations within the Great Marsh promote conservation, protection, and open space.  The Massachusetts Natural Heritage and Endangered Species Program database indicates that the Parker River / Essex Bay ACEC and Great Marsh provide habitat for 35 animal and plant species listed as “rare” and protected under the States Endangered Species Act. Plant and animal species are also protected under the State’s Wetland Protection Act and  implementing regulations.

Some 67,000 shorebirds representing more than 30 species have been recorded at the Great Marsh, making it one of the nation’s top birdwatching spots.  A study conducted on shorebird use of impoundments at the Parker River NWR determined that the Refuge plays a more important role during the fall migration. Past and current shorebird monitoring activities include standardized bi-monthly shorebird surveys on the Refuge, and Great Marsh Coalition participation in the International Shorebird Survey (ISS) and Massachusetts Audubon surveys. 

The major disturbance to shorebirds continues to be human-related recreational pursuits, namely all traditional beach-use activities, free-roaming pets, off-road vehicle (ORV) usage, boating, and  shell-fishing.  A study under consideration by the Refuge would determine the impacts of various public-use beach activities on shorebirds. In addition to human disturbance, storm events and extreme high tides cause nest abandonment and destruction for some shorebird species.  Avian and terrestrial predation also are important factors limiting nesting success and  shorebird production.

Shorebird species at the Great Marsh include:

Black-bellied Plover (Pluvialis squatarola)
American Golden-Plover (Pluvialis dominica)
Semipalmated Plover (Charadrius semipalmatus)
Piping Plover (Charadrius melodus)
Killdeer (Charadrius vociferous)
Greater Yellowlegs (Tringa melanoleuca)
Lesser Yellowlegs (Tringa flavipes)
Solitary Sandpiper (Tringa solitaria)
Willet (Catoptrophorus semipalmatus)
Spotted Sandpiper (Actitis macularia)
Upland Sandpiper (Bartramia longicauda)
Whimbrel (Numenius phaeopus)
Hudsonian Godwit (Limosa haemastica)
Marbled Godwit (Limosa fedoa)
Ruddy Turnstone (Arenaria interpres)
Red Knot (Calidris canutus)
Sanderling (Calidris alba)
Semipalmated Sandpiper (Calidris pusilla)
Western Sandpiper (Calidris mauri)
Least Sandpiper (Calidris minutilla)
White-rumped Sandpiper (Calidris fuscicollis)
Baird's Sandpiper (Calidris bairdii)
Pectoral Sandpiper (Calidris melanotos)
Dunlin (Calidris alpina)
Stilt Sandpiper (Calidris himantopus)
Buff-breasted Sandpiper (Tryngites subruficollis)
Short-billed Dowitcher (Limnodromus griseus)
Long-billed Dowitcher (Limnodromus scolopaceus)
Common Snipe (Gallinago gallinago)
American Woodcock (Scolopax minor)
Wilson's Phalarope (Phalaropus tricolor)
Red-necked Phalarope (Phalaropus lobatus)

Threats to Great Marsh Habitats

The continued development of lands adjacent to the Great Marsh does pose threats, as do high bacterial counts from poorly functioning septic systems. Pet waste and livestock- and horse-pasture manure piles contaminate waterways and shellfish beds. Invasive wetland plants are widespread and are encouraged by tidal restrictions. Erosion of salt marsh banks due to speeding boats and jet skis pose threats to the integrity of the marsh.


Management challenges include:  invasive plants, tidal restrictions, salt marsh ditching, mosquito-control issues, and point and non-point source pollution sources. There is an interest and described need to seed unproductive shellfish beds, and shellfish aquaculture research that addresses potential impacts of this to shorebirds needs to be conducted.

Special Information

On August 19, 2008, the Great Marsh WHSRN Site dedication event takes place at the Parker River National Wildlife Refuge. This event coincides with the official opening of the new bridge recently finished at the refuge’s headquarters.

Contact Us

Primary Contact:

Frank Drauszewski
Deputy Refuge Manager, Parker River NWR
U.S. Fish and Wildlife Service
6 Plum Island Turnpike
Newburyport, MA 01950
(978) 465-5753 x204

Other Partners:

Massachusetts Audubon Society
346 Grapevine Road
Wenham, MA 01984
(978)927-1122 (attn: Kathy Leahy)
(978)462-9998 (Joppa Flats Nature Center, attn: Bill Gette)

The Trustees of Reservations
Northeast Regional Office
290 Argilla Road
Ipswich, MA 01938

Essex County Greenbelt Association
82 Eastern Ave.
Essex, MA 01929
(978) 768-7241 (attn: Dave Rimmer)

Parker River Clean Water Association
P.O. Box 798
Byfield, MA 01922
(978) 462-2551 (attn: Don Bade)

Eight Town and the Bay Committee
c/o Merrimack Valley Planning Commission
160 Main Street
Haverhill, MA 01830
(978) 374-0519

Friends of Parker River Refuge
P.O. Box 184
Newburyport, MA 01950

Essex National Heritage Commission
140 Washington Street
Salem, MA 01970
(978)740-0444 (attn: Annie Harris)