Burlington is a city in Burlington County, in the U.S. state of New Jersey. It is a suburb of Philadelphia. As of the 2020 United States census, the city's population was 9,743, a decrease of 177 from the 2…Burlington is a city in Burlington County, in the U.S. state of New Jersey. It is a suburb of Philadelphia. As of the 2020 United States census, the city's population was 9,743, a decrease of 177 from the 2010 census count of 9,920, which in turn reflected an increase of 184 from the 9,736 counted in the 2000 census.