Jacksonville, Florida is 11 times larger than Washington, D.C..
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
Area: 178 km2 calculated
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. Wikipedia