There are 21 US Post Offices in Duval County serving a total of 636,439 residents equating to 30,307 residents per post office. It's estimated that approximately 1,015,828 packages are handled across the 21 county post offices annually. 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."