Jonesborough (formerly spelled Jonesboro) is a town in and the county seat of Washington County, Tennessee, in the southeastern United States. The population was 4,168 at the 2000 census. It is Tennessee's oldest town.
Jonesborough is part of the Johnson City 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.
Jonesborough was founded in 1779, 17 years before Tennessee became a state. It was named after North Carolina legislator, Willie Jones, who supported North Carolina's westward expansion over the Appalachian Mountains.