Jacksonville, Florida is 2.9 times larger than Singapore.
Area: 697 km2 World Factbook
Population: 5,567,301 (July 2014) World Factbook
Singapore, officially the Republic of Singapore, is a sovereign city-state and island country in Southeast Asia. It lies off the southern tip of the Malay Peninsula and is 137 kilometres north of the equator. Wikipedia
Area: 1,988 km2 calculated
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