Leonardo is an unincorporated community and census-designated place (CDP) located on the north shore of Middletown Township, in Monmouth County, New Jersey, United States. The community is situated along the Raritan Bayshore and is part of the Jersey Shore region of the state. As of the 2020 United States census, the CDP's population was 2,549, which in turn had reflected a decline of 66 (-2.3%) from the 2,823 counted at the 2000 census.
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.
Geography
Leonardo is located in northern Monmouth County, on the south shore of Raritan Bay. It is in northern Middletown Township and is bordered to the east by the borough of Atlantic Highlands and to the west by unincorporated Belford. New Jersey Route 36 forms the southern border of the Leonardo CDP; the highway runs east to Highlands and west to Keyport.
According to the U.S. Census Bureau, the Leonardo CDP has a total area of , including of water (1.00%).
| 38| 41| 48| 60| 70| 79| 85| 83| 75| 65| 53| 44 <!--highs-->
| 25| 26| 32| 40| 50| 59| 67| 65| 57| 48| 37| 29 <!--lows-->
|3.2|2.4|3.5|3.2|3.6|3.5|3.9|3.9|3.6|3.0|2.7|3.5 <!--rain-->
|7.5|8.6|4.3|0.7|0.0|0.0|0.0|0.0|0.0|0.0|0.4|4.7 <!--snow-->