Dungannon is a town in Scott County, Virginia. The population was 257 at the 2020 census. It was named after the town of Dungannon in County Tyrone, Northern Ireland. Dungannon is part of the Kingsport-Bristol-Bristol, TN-VA Metropolitan Statistical Area, which is a component of the Johnson City-Kingsport-Bristol, TN-VA Combined Statistical Area – commonly known as the "Tri-Cities" region.