Old Bethpage Home Inspections Completed Full Inspections In Old Bethpage 9/8/2018 34 Prescott Pl 8/30/2015 18 Beatrice Ln 5/26/2014 7 Lido Pl 4/15/2013 15 Cedar Drive E 4/9/2013 19 Wilford St 10/22/2012 5 Adrienne Dr Back to Completed Home Inspections Old Bethpage is a hamlet and census-designated place (CDP) located on Long Island in the Town of Oyster Bay, Nassau County, New York, USA. The population of the CDP was 5,523 at the 2010 census. It is served by the Old Bethpage Post Office, ZIP code 11804. Old Bethpage and its neighboring hamlet, Plainview, share a school system, library, fire department and water district. Law enforcement for the community is provided by theNassau County Police Department's Eighth Precinct.