Jacksonville, Florida is 31 times larger than Newark, New Jersey.
Area: 1,988 km2 calculated
Population: 836,507 (2012)
Jacksonville is the largest city in the U.S. state of Florida by population and the largest city by area in the contiguous United States. It is the county seat of Duval County, with which the city government consolidated in 1968. Wikipedia
Area: 63 km2 calculated
Population: 277,727 (2012)
Newark is the largest city in the U.S. state of New Jersey, and the county seat of Essex County. Wikipedia