There are 10 US Post Offices in Madison County serving a total of 133,793 residents equating to 13,379 residents per post office. It's estimated that approximately 213,549 packages are handled across the 10 county post offices annually. Madison County is a county located in the U.S. state of Tennessee. As of the 2010 census, the population was 98,294. Its county seat is Jackson. Madison County is included in the Jackson, TN Metropolitan Statistical Area."