Hauppauge is a hamlet and census-designated place (CDP) in the towns of Islip and Smithtown in Suffolk County, New York on Long Island. The population was 20,882 at the time of the 2010 census. Despite Riverhead being the county seat, many government offices are located in Hauppauge.

Islip is a town in Suffolk County, New York, United States, on the South Shore of Long Island. The population was 335,543 at the 2010 census, making it the fourth most populous city or town in the New York metropolitan area.