There are 3 US Post Offices in Madison County serving a total of 21,474 residents equating to 7,158 residents per post office. It's estimated that approximately 34,275 packages are handled across the 3 county post offices annually. Madison County is a county located in the U.S. state of North Carolina. As of the 2010 census, the population was 20,764. Its county seat is Marshall. The county was formed in 1851 from parts of Buncombe County and Yancey County. It was named for James Madison, fourth President of the United States (1809\u20131817). Madison County is part of the Asheville, NC Metropolitan Statistical Area.