Allentown is a borough in Monmouth County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 1,828, reflecting a decline of 54 (-2.9%) from the 1,882 counted in the 2000 Census, which had in turn increased by 54 (+3.0%) from the 1,828 counted in the 1990 Census.
Allentown was incorporated as a borough by an act of the New Jersey Legislature on January 29, 1889, from portions of Upper Freehold Township, based on the results of a referendum held that day. The borough was named for settler Robert Burnet's son-in-law, Nathan Allen or for William Allen, who served as Chief Justice of the Province of Pennsylvania.
Allentown's shopping district has antique and specialty shops, as well as restaurants. Many historic homes and historic buildings are located in the borough. The Horse Park of New Jersey is a park located near the borough but does have an Allentown mailing address. Heritage Park is located within the borough near the shopping district.
The borough received the 'Village Center' designation in 2002, which will allow the borough to receive additional state aid aimed at preserving historic and natural resource sites that are at risk.
According to the United States Census Bureau, the borough had a total area of 0.62 square miles (1.61 km2), including 0.60 square miles (1.54 km2) of land and 0.03 square miles (0.06 km2) of water (4.03%).
Allentown borders the municipalities of Upper Freehold Township in Monmouth County and Robbinsville Township in Mercer County.
The 2010 United States Census counted 1,828 people, 704 households, and 499.136 families in the borough. The population density was 3,023.9 inhabitants per square mile (1,167.5/km2). There were 735 housing units at an average density of 1,215.8 per square mile (469.4/km2). The racial makeup was 90.97% (1,663) White, 4.43% (81) Black or African American, 0.11% (2) Native American, 1.53% (28) Asian, 0.00% (0) Pacific Islander, 0.88% (16) from other races, and 2.08% (38) from two or more races.