There are 24 US Post Offices in Mclean County serving a total of 158,653 residents equating to 6,611 residents per post office. It's estimated that approximately 253,228 packages are handled across the 24 county post offices annually. McLean County is the largest county by land area in the U.S. state of Illinois. According to the 2010 census, it had a population of 169,572. Its county seat is Bloomington. McLean County is included in the Bloomington\u2013Normal, IL Metropolitan Statistical Area."