Ronkonkoma (pronounced ron-KONK-uh-muh) is a census-designated place (CDP) and hamlet in the Town of Islip, Suffolk County, New York, United States. The population was 20,029 at the 2000 census. The Ronkonkoma post office has the ZIP code of 11779, and serves parts of several hamlets and CDPs adjacent to Ronkonkoma also. Since 1988, Ronkonkoma has been the end of electrification along the Long Island Rail Road's Main Line, leading most service along the line to be referred to as Ronkonkoma Branch service. Ronkonkoma is also home to the Town of Islip owned and operated Long Island MacArthur Airport (sometimes referred to only as Islip), airport code ISP. The New York Air Route Traffic Control Center is located in Ronkonkoma, as is CVD Equipment Corporation, a nanotechnology and high-technology engineering company that is doing research on carbon nanotubes in cooperation with the University of Cincinnati in Ohio.