Hewlett is a hamlet and census-designated place (CDP) in Nassau County, New York on the South Shore of Long Island. As of the United States 2010 Census, the CDP population was 6,819. Hewlett Bay Park and Hewlett Harbor consist of many mansions and harbor villas with very large property, a few dating back to the time of the American Revolution. This area, like Back/Old Lawrence is unique because its rural affluence is similar in character to the more well known Gold Coast of the North Shore instead of being more urbanized like the rest of the South Shore of Nassau County.
Hewlett is usually included as one of the Five Towns in the southwestern corner of Nassau County. In the context of the Five Towns, "The Hewletts" or "Hewlett" is often used to refer collectively to the hamlet of Hewlett, together with the villages of Hewlett Bay Park, Hewlett Harbor and Hewlett Neck, along with Woodsburgh.