Bordentown is a city in Burlington County, in the U.S. state of New Jersey. As of the 2020 United States census, the city's population was 3,993, an increase of 69 (+1.8%) from the 2010 census count of 3,924, which in turn reflected a decline of 45 (−1.1%) from the 3,969 counted in the 2000 census.