Bethpage is a hamlet located on Long Island within the Town of Oyster Bay in Nassau County, New York, United States, as well as a census-designated place with borders slightly different from those of the hamlet. The CDP's population was 16,429 at the 2010 United States Census.The area is served by the Bethpage Post Office, ZIP code 11714, whose boundaries are slightly different from that of the CDP. The area is also served by Bethpage Union Free School District, Island Trees Union Free School District, Plainedge Union Free School District, and Hicksville Union Free School District, the boundaries of which include parts of some surrounding hamlets, including parts of Old Bethpage, Plainview, and Plainedge. The Town of Hempstead, on its website, includes a small part of Bethpage hamlet that is in the Levittown census-designated place.