Milltown is a borough in Middlesex County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 6,893, reflecting a decrease of 107 (-1.5%) from the 7,000 counted in the 2000 Census, which had in turn increased by 32 (+0.5%) from the 6,968 counted in the 1990 Census.
Milltown was incorporated as a borough by an Act of the New Jersey Legislature on January 29, 1889, from portions of North Brunswick Township, based on the results of a referendum held three days earlier. The borough was reincorporated by resolution of the borough council on May 2, 1896. A portion of East Brunswick Township was annexed in 1902.