The Great Swamp and its 63,000-acre watershed stretches twenty miles through the towns of Pawling and Dover in Dutchess County, and Southeast and Patterson (in Putnam County). The Great Swamp spans two watersheds, dividing in Pawling into a north and south flow. The southern section flows into the East Branch Croton River, to the East Branch Reservoir of New York City's Croton Reservoir System, making the Great Swamp the important headwaters of New York City's drinking water supply.
The Mission of the Friends the Great Swamp (FrOGs) is to undertake activities "to conserve, protect, and promote the functions, values and integrity of the Great Swamp wetland and its watersheds in Putnam and Dutchess Counties, New York". FrOGS holds regular meetings and events - All meetings are open to the public and volunteers are welcome! For more informaiton, see the contact information, FrOGS website, and FrOGS Section of the Community Forum.