There are 4 US Post Offices in Jackson County serving a total of 9,492 residents equating to 2,373 residents per post office. It's estimated that approximately 15,150 packages are handled across the 4 county post offices annually. Jackson County is a county located in the U.S. state of Tennessee. As of the 2010 census, the population was 11,638. Its county seat is Gainesboro. Jackson is part of the Cookeville, TN Micropolitan Statistical Area."