Smyth County is a county located in the U.S. state of Virginia. As of the 2020 census, the population was 29,800. Its county seat is Marion.

Marion is a town in, and the county seat of, Smyth County, Virginia, United States. It is positioned upon Interstate 81, in the Blue Ridge portion of the Southern Appalachian mountains in Southwest Virginia. The town is named for American Revolutionary War officer Francis Marion. The town limits had a population of approximately 6,000, per 2020 Census estimates. However, together with the neighborhoods, an additional 9,000 residents residing in unincorporated Smyth County have Marion mailing addresses, granting the Marion, VA ZIP code (24354) a total population of about 14,500, which is around half of the county's total population.