Plainview is a hamlet and census-designated place (CDP) located near the North Shore of Long Island in the town of Oyster Bay, Nassau County, New York, USA. The population of the CDP was 26,217. The Plainview post office has the ZIP code 11803.
Plainview and its neighboring hamlet, Old Bethpage, share a school system, library, fire department, and water district. Law enforcement for the communities is provided by the Nassau County Police Department's, Second Precinct. Plainview is split between the 2nd congressional district of New York and the 3rd congressional district of New York.