Milltown is a Borough in Middlesex County, New Jersey, United States. As of the United States 2000 Census, the borough population was 7,000. 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 day earlier. The borough was incorporated by resolution of the borough council on May 2, 1896. A portion of East Brunswick Township was annexed in 1902. As of the 2000 Census, the center of population for New Jersey was located in Milltown, at Milltown Road, just east of the New Jersey Turnpike. Miltown, the groundbreaking anxiolytic and sedative drug that first came to market in the mid-1950s, was named after the town of Milltown.