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.
All the communities within Hewlett are part of the Hewlett-Woodmere School District or the Lynbrook Union Free School District.
The hamlet's name comes from the Hewlett family. George Hewlett, the first Hewlett to settle in the area, was born in England in 1634. He was part of an English community which emigrated to Long Island - by way of Connecticut - and negotiated treaties with the Dutch governors and native inhabitants to establish a population center in what is now Hempstead.
Hewlett is located at 40°38′31″N 73°41′39″W.
According to the United States Census Bureau, the CDP has a total area of 0.9 square miles (2.3 km2), of which 0.9 square miles (2.3 km2) is land and 1.11% is water.
As of the census of 2010, there were 6,819 people, 2,547 households, and 1,833 families residing in the CDP. The population density was 7,936.0 per square mile (3,062.8/km2).