There are 5 US Post Offices in Smyth County serving a total of 32,454 residents equating to 6,491 residents per post office. It's estimated that approximately 51,800 packages are handled across the 5 county post offices annually. Smyth County is a county located in the U.S. state of Virginia. As of the 2010 census, the population was 32,208. Its county seat is Marion.