what county jacksonville fl
Duval County, Florida. Duval County is a county located in the State of Florida. As of the 2010 census, the population was 864,263, with a 2015 estimate at 913,010. Its county seat is Jacksonville, with which the Duval County government has been consolidated since 1968. Duval County was established in 1822, and is named for William Pope Duval, Governor of Florida Territory from 1822 to 1834. Duval County is included in the Jacksonville, FL Metropolitan Statistical Area.