North Caldwell is a borough in northwestern Essex County, New Jersey, United States, and a suburb of New York City. As of the 2010 United States Census, the borough's population was 6,183, reflecting a decline of 1,192 (-16.2%) from the 7,375 counted in the 2000 Census, which had in turn increased by 669 (+10.0%) from the 6,706 counted in the 1990 Census.
North Caldwell was incorporated by an Act of the New Jersey Legislature on March 31, 1898, from portions of Caldwell Township (now known as Fairfield Township). In 1982, North Caldwell became a township to take advantage of federal revenue sharing policies. Effective January 1, 1992, it again became a borough.
New Jersey Monthly magazine ranked North Caldwell as its 10th best place to live in its 2010 rankings of the "Best Places To Live" in New Jersey.
The former Essex County Penitentiary, constructed in 1872 and last used as the Essex County Jail Annex in 2004, was sold to K. Hovnanian and will be redeveloped with housing. Since 1920, the inmates at the jail had been included in the borough's population statistics by the Census Bureau.