There are 3 US Post Offices in Calhoun County serving a total of 13,690 residents equating to 4,563 residents per post office. It's estimated that approximately 21,851 packages are handled across the 3 county post offices annually. Calhoun County is a county located in the U.S. state of Florida. As of the 2010 census, the population was 14,625, making it the fifth-least populous county in Florida. Its county seat is Blountstown."