Hazlet is a township in Monmouth County, New Jersey, United States. As of the 2010 United States Census, the township's population was 20,334, reflecting a decline of 1,044 (-4.9%) from the 21,378 counted in the 2000 Census, which had in turn declined by 598 (-2.7%) from the 21,976 counted in the 1990 Census.
What is now Hazlet Township was originally incorporated as Raritan Township by an act of the New Jersey Legislature on February 25, 1848, from portions of Middletown Township. Portions of the township were taken to form Holmdel Township (February 23, 1857), Matawan Township (also February 23, 1857, now Aberdeen Township), Keyport (March 17, 1870), Keansburg (March 26, 1917) and Union Beach (March 16, 1925). The township was renamed "Hazlet Township" as of November 28, 1967, based on the results of a referendum held on November 7, 1967. Hazlet derived its name from a Dr. John Hazlett who had an estate in Raritan Township near the Keyport-Holmdel Turnpike, now Holmdel Road.
Hazlet is part of the Bayshore Regional Strategic Plan, an effort by nine municipalities in northern Monmouth County to reinvigorate the area's economy by emphasizing the traditional downtowns, dense residential neighborhoods, maritime history, and the natural beauty of the Raritan Bayshore coastline.