Jamesburg is a borough in Middlesex County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 5,915, reflecting a decline of 110 (-1.8%) from the 6,025 counted in the 2000 Census, which had in turn increased by 731 (+13.8%) from the 5,294 counted in the 1990 Census.
Jamesburg was formed as a borough by an act of the New Jersey Legislature on March 19, 1887, when it was created from portions of Monroe Township, based on the results of a referendum held on March 15, 1887. Jamesburg's incorporation was confirmed on April 15, 1915.
The borough was named for James Buckelew, who established a mill that became the nucleus of what is now Jamesburg. After Monroe Township officials refused to admit an African-American student into one of its schools, Buckelew funded the construction of a school located at the corner of Church Street and Gatzmer Avenue that would be open to all children. The school was named in his honor and became the derivation of the borough's name.
On July 17, 2005, approximately 7 to 8 inches (18 to 20 cm) of rain fell in Jamesburg, flooding areas on West Railroad Avenue, East Church Street, Pergola Avenue, Willow Street, Forsgate Drive, and Gatzmer Avenue. Roughly 75 to 100 families were evacuated from their homes and housed at the John F. Kennedy Elementary School.
According to the United States Census Bureau, the borough had a total area of 0.883 square miles (2.289 km2), including 0.877 square miles (2.272 km2) of land and 0.006 square miles (0.016 km2) of water (0.71%).
The borough is the older and more urban core area located in the center of and completely surrounded by Monroe Township, making it part of 21 pairs of "doughnut towns" in the state, where one municipality entirely surrounds another.
The 2010 United States Census counted 5,915 people, 2,172 households, and 1,492.164 families in the borough. The population density was 6,741.8 per square mile (2,603.0/km2). There were 2,267 housing units at an average density of 2,583.9 per square mile (997.6/km2). The racial makeup was 73.90% (4,371) White, 8.84% (523) Black or African American, 0.85% (50) Native American, 4.53% (268) Asian, 0.00% (0) Pacific Islander, 9.42% (557) from other races, and 2.47% (146) from two or more races. Hispanic or Latino of any race were 22.38% (1,324) of the population.
Of the 2,172 households, 36.0% had children under the age of 18; 51.0% were married couples living together; 12.3% had a female householder with no husband present and 31.3% were non-families.