There are 13 US Post Offices in Jackson County serving a total of 82,260 residents equating to 6,328 residents per post office. It's estimated that approximately 131,296 packages are handled across the 13 county post offices annually. Jackson County is a county located in the U.S. state of Illinois with a population of 60,218 at the 2010 census. Its county seat is Murphysboro, and its most populous city is Carbondale, home to the main campus of Southern Illinois University. The county was incorporated on January 10, 1816 and named for Andrew Jackson. Jackson County is included in the Carbondale-Marion, IL Metropolitan Statistical Area. It is located in the southern portion of Illinois known locally as \"Little Egypt\"."