New Providence is a borough on the northwestern edge of Union County, New Jersey, United States. It is located on the Passaic River, which forms the county boundary with Morris County. As of the 2010 United States Census, the population was 12,171, reflecting an increase of 264 from the 11,907 counted in the 2000 Census, which had in turn increased by 468 from the 11,439 counted in the 1990 Census.