Hillcrest is a hamlet incorporated in 1893 and census-designated place, in the town of Ramapo, Rockland County, New York, United States. It is located north of Spring Valley, east of Viola, south of New Square and New Hempstead, and west of New City. The population was 8,164 at the 2020 census. It is a bedroom suburb of New York City, as many residents commute to employment in Manhattan by bus, train or automobile. It is primarily served by the Spring Valley post office.