Caldwell is a borough located in northwestern Essex County, New Jersey, about 16 miles outside of New York City. As of the 2010 United States Census, the borough's population was 7,822, reflecting an increase of 238 from the 7,584 counted in the 2000 Census, which had in turn increased by 35 from the 7,549 counted in the 1990 Census.Caldwell was incorporated as a borough by an act of the New Jersey Legislature on February 10, 1892, from portions of Caldwell Township, based on the results of a referendum held on the previous day.