Dungannon is a town in Scott County, Virginia, United States. The population was 317 at the 2000 census. It derives its name from the medium-sized town, Dungannon, situated in County Tyrone in Northern Ireland.Dungannon is part of the Kingsport–Bristol (TN)–Bristol (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.