The Hudson River Reserve encompasses about 5,000 acres of freshwater and brackish tidal wetlands and uplands distributed at four sites that span the middle 100 miles of the Hudson River Estuary. From north to south the sites are: Stockport Flats, Tivoli Bays, Iona Island and Piermont Marsh. The tidal Hudson River links the communities of its valley economically, culturally and ecologically and has been a cradle of human development for thousands of years. A nursery for such important fish as sturgeon, striped bass and American shad, the river is home to more than 200 species of fish. It supports a corresponding abundance of other river-dependent wildlife, especially birds. Profoundly influenced by the ocean's tides for more than half its length, the Hudson River estuary stretches 153 miles and includes a wide range of wetland habitats, from the brackish marshes of Piermont to the slightly brackish wetlands of Iona Island, and the freshwater tidal mudflats and marshes of Tivoli Bays and Stockport Flats. The Reserve's headquarters and visitors center is located at the Norrie Point Environmental Center in Staatsburg, NY.

The Hudson River Reserve is a network of four coastal wetlands located along 100 miles of the Hudson Estuary in New York state. The Reserve components are: Piermont Marsh and Iona Island, in Rockland County; Tivoli Bays, in Dutchess County; and Stockport Flats, in Columbia County.