Greenfield Park is a hamlet in the Town of Wawarsing, Ulster County, New York, United States. The community is located along New York State Route 52, 4.7 miles west of Ellenville. Greenfield Park has a post office with ZIP code 12435, which opened on December 23, 1852. It is home to many bungalow colonies which are summer homes for mostly Jewish families who escape the summer heat in Brooklyn including tamarack hills, greenfield meadows, Dee lees.