Stockton is a borough in Hunterdon County, New Jersey, United States. The borough sits on the Delaware River at the western end of Amwell Valley. As of the 2010 United States Census, the borough's population was 538, reflecting a decline of 22 (−3.9%) from the 560 counted in the 2000 Census, which had in turn declined by 69 (−11.0%) from the 629 counted in the 1990 Census. Stockton was incorporated as a borough by an act of the New Jersey Legislature on April 14, 1898, from portions of Delaware Township.