New York

The Great Swamp

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The Great Swamp is an ecological treasure nestled in the rapidly developing southern Harlem Valley.  One of the largest wetlands in New York State, it is located less than 60 miles from New York City in eastern Putnam and Dutchess Counties.  This wetland stretches nearly 20 miles across the five municipalities of Southeast, Patterson, Pawling Town, Pawling Village and Dover and covers nearly 6,000 acres.

Great Swamp Study cover 200x267

Read a study of watershed conservation conducted in The Great Swamp.

The Great Swamp provides ecological services that directly and indirectly benefit every resident of the watershed.  The Great Swamp improves water quality, recharges the aquifer, reduces flooding, provides critical habitat for plants and animals and creates open space for recreation and scenic views.  For the 40,000+ residents who live near the swamp and the more than one million people who depend on it for drinking water, the Great Swamp is a vital natural resource.

Despite the value of this ecosystem, the Great Swamp is threatened.  The watershed is at the edge of advancing suburban development expanding north from Westchester County and New York City.  The area's rural quality of life and easy access to major commercial centers makes the watershed an attractive place to live and do business. 

Growth and development trends in the watershed are very likely to continue.  Thus, conservation of the Great Swamp and enhancement of the local quality of life depend on development and economic growth that are compatible with the environment and consistent with community goals. 

The Nature Conservancy's Eastern New York Chapter started its Great Swamp Program in 1996 to engage residents and local leaders in the protection of the native plants and animals in the Great Swamp watershed, while preserving the economic vitality of the local communities within it.  Strategies to conserve the Great Swamp and foster compatible economic growth include:

  • Increase public awareness of the Great Swamp
  • Foster local leadership on wetland and watershed protection
  • Strengthen wetland protections
  • Improve water quality
  • Protect plant and animal habitat
  • Encourage compatible economic development and improved land-use planning

Much of the watershed is currently unaltered by residential, commercial or agricultural uses.  This creates the illusion of large tracts of land that will remain rural open space forever.  However, most of this land is privately owned.  Under current zoning, much of it could be transformed into residential or commercial developments.  The Eastern New York Chapter's conservation work in the Great Swamp focuses on land protection throughout the watershed, but particularly in the Pine Island region, an area of the swamp known as the "heart of the Swamp"  The chapter's goal is to establish a 500-acre conservation area within this region. 



Because of its large size and diverse landscapes, the Great Swamp supports a variety of educational and recreational uses.  While the wetlands do not lend themselves to walking or hiking, there are numerous trail networks located near the Great Swamp and throughout the watershed. 

The most notable is the Appalachian Trail, which traverses the wetland in northern Pawling and is accessible by Metro-North Railroad, or from Route 22 or Route 55.  Patterson Environmental Park and William Clough Preserve, Twin Hill Preserve and Doansburg Preserve each offer trails near the wetland. 

Several locations offer access for canoeing and kayaking.  These include:

  • Green Chimneys School (Doansburg Road at the Southeast/Patterson town line. Call for information 845-279-2995)
  • Patterson Environmental Park (South Street in the Hamlet of Patterson. Call for information 845- 878-6500). 

Please be advised that during times of low flow, these areas may be inaccessible to small craft.

Wetlands are among the most important and most biologically productive natural ecosystems on Earth, and the Great Swamp reflects this biological richness through an amazing diversity of plants animals and natural communities. While red hardwood maple swamp is the most dominant community within the Great Swamp, there is a wide occurrence of floodplain forest and shrub swamp communities, as well as rare inland Atlantic white cedar swamp and several very rare, high quality fen communities.

The Great Swamp harbors at least 20 species of mammals, 36 species of amphibians and reptiles, 64 species of butterflies, and 58 species of dragonflies and damselflies.  A recent inventory identified 180 species of birds using the Great Swamp as a migratory flyway and 100 species nesting in the wetland and adjacent upland areas.


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