Leonardo is an unincorporated community and census-designated place (CDP) within Middletown Township, in Monmouth County, New Jersey, United States. As of the 2010 United States Census, the CDP's population was 2,757. The ZIP code for Leonardo is 07737.
Leonardo is named for Henry and James Leonard, the first ironmasters of New Jersey.
During World War II, the large dock complex of Naval Weapons Station Earle was built to supply ammunition to the forces.
Leonardo is known as the site of the only casualties of the US Nike Missile program. On May 22, 1958, an Ajax missile exploded at the Nike missile base in Leonardo, killing six soldiers and four civilians. Since the Project Nike shutdown in 1974, the Leonardo launch base, designated NY-53, has been redeveloped into single-family home sites.
Leonardo is located on the south shore of Raritan Bay. According to the United States Census Bureau, Leonardo had a total area of 0.603 square miles (1.562 km2), including 0.595 square miles (1.540 km2) of land and 0.008 square miles (0.021 km2) of water (1.38%).
The 2010 United States Census counted 2,757 people, 1,001 households, and 741.741 families in the CDP. The population density was 4,636.1 per square mile (1,790.0/km2). There were 1,055 housing units at an average density of 1,774.1 per square mile (685.0/km2). The racial makeup was 95.47% (2,632) White, 1.02% (28) Black or African American, 0.15% (4) Native American, 1.02% (28) Asian, 0.00% (0) Pacific Islander, 0.91% (25) from other races, and 1.45% (40) from two or more races.