Phillipsburg is a town located along the Delaware River that is the most populous municipality in Warren County, in the U.S. state of New Jersey. It is part of the Allentown-Bethlehem-Easton, PA-NJ metropolitan statistical area. As of the 2020 United States census, the town's population was 15,249, an increase of 299 from the 2010 census count of 14,950, which in turn reflected a decline of 216 from the 15,166 counted in the 2000 census.