The core of the marsh includes both high and low marsh communities extending from U. S. Route 1 south to the harbor at Pine Point. The total size is approximately 3,000 acres making it Maine?s largest contiguous saltmarsh. It is fed by three major tributaries: the Scarborough, Nonesuch, and Libby Rivers. Two partially impounded tidal areas, Dunstan?s Landing and areas behind what is commonly referred to as the Pelreco Building, provide a hydrological regime different than other portions of the marsh, and thus attract large seasonal concentrations of waterfowl and wading birds including: Blue and Green-winged Teal, Ring-necked Duck, American Black Duck, American Wigeon, Gadwall, Northern Shoveler, and Northern Pintail, among others. At low tide, extensive mudflats become available along the Scarborough River.
The marsh supports breeding habitat for both Nelson?s and Saltmarsh Sharp-tailed Sparrows, probably the most significant breeding site for these species in Maine. Nelson?s/Saltmarsh hybrids may be seen here as well. Least Bitterns have been recorded breeding in the freshwater wetlands surrounding the marsh. Many species of wading birds can be seen feeding in the large salt panne complexes (especially at the outlet of the Libby River, south of the Eastern Road and along U.S. Route 1). Among this network of tidal creeks and pannes, wading birds including Glossy Ibises, American Oystercatchers, Great Blue and Little Blue Herons, Snowy and Great Egrets can be seen feeding. This site also provides feeding habitat for many species of migrating shorebirds including: Whimbrels, Short and Long-billed Dowitchers, Dunlin, Least and Semipalmated Sandpipers, and Red-necked Phalaropes.
Human impact has long been an issue at Scarborough Marsh. The U. S. Fish and Wildlife Service is currently working with the U. S. D. A. Natural Resources Conservation Service and other partners to restore tidal flow and control the spread of invasive species in the northern reaches of the marsh. Some of this work results from mitigation efforts following the Julie N oil spill in 1996. In addition, some effort has been put forth to plug ditches that were dug to facilitate the harvest of salt hay. Recent research on Sharp-tailed Sparrows at this site revealed that this species accumulates high levels of mercury from the marsh. Whether the levels affect reproductive success is unclear, but it suggests that human activities around the marsh is significant and may be affecting the ecology of the marsh.
The Maine Department of Inland Fisheries and Wildlife owns and manages the area. Maine Audubon maintains an education center there where canoes can be rented for exploring tidal creeks. The easiest foot access is via Pine Point Road (Route 9) where it meets the Eastern Trail, approximately 1.5 miles south of U. S. Route 1. Parking is provided in a small gravel lot; dogs must remain on leash.