Marshlands Conservancy is a 147-acre nature preserve in the city of Rye, New York, that is fully owned and operated by Westchester County Parks. It has numerous wildlife habitats from ponds to creeks to a large meadow area, succession forest, freshwater wetlands and the only extensive salt marsh in Westchester. It borders Long Island Sound and can be entered via an easement on the historic Boston Post Road. It is one of 5 properties that together constitute the Boston Post Road Historic District. It has high archaeological sensitivity. The conservancy has also been designated an Important Bird Area.