There are 7 US Post Offices in Saline County serving a total of 25,440 residents equating to 3,634 residents per post office. It's estimated that approximately 40,605 packages are handled across the 7 county post offices annually. Saline County is a county located in the U.S. state of Illinois. According to the 2010 census, it had a population of 24,913. Its county seat is Harrisburg. It is located in the southern portion of Illinois known locally as \"Little Egypt\". Saline County is home to the largest KFC in the United States. There are three major towns in Saline County connected by U.S. Route 45, and formerly by the now abandoned Cairo and Vincennes/Big Four/New York Central Line, from north to south, Eldorado, Harrisburg, and Carrier Mills. Saline County is currently the 79th wealthiest county in the state, out of 102."