Bethpage is a hamlet (and also the name of a census-designated place with slightly different borders) located within the Town of Oyster Bay in Nassau County, New York, United States. The CDP's population was 16,543 at the 2000 United States Census. The hamlet is served by its own school district, the boundaries of which include parts of some surrounding hamlets including Old Bethpage and Plainedge. The ZIP code for most of the hamlet is 11714 except for the most northeastern portion which lies in the Old Bethpage postal district of 11804. The town of Hempstead, on its website, includes a small part of Bethpage hamlet that is in the Levittown census-designated place.