Blountville is a small town located in Sullivan County, Tennessee, United States. It is the county seat of Sullivan County and is part of the Kingsport-Bristol Metropolitan Statistical Area. Blountville has a population of approximately 3,000 residents. The town is known for its historical sites, including the Sullivan County Courthouse, which is the second oldest courthouse still in use in Tennessee. Blountville is also home to the Tri-Cities Regional Airport, which serves the greater Tri-Cities area.