There are 7 US Post Offices in Coles County serving a total of 54,871 residents equating to 7,839 residents per post office. It's estimated that approximately 87,580 packages are handled across the 7 county post offices annually. Coles County is a county located in the U.S. state of Illinois. As of the 2010 census, the population was 53,873. Its county seat is Charleston, which is also the home of Eastern Illinois University. Coles County is part of the Charleston-Mattoon, IL Micropolitan Statistical Area."