The value of all farms and rural land for sale in Sullivan County recently was $314 million, representing a total of 3,682 acres of land for sale in Sullivan County. Sullivan County ranks fourth out of 95 counties in the state for the total number of acres of land currently advertised for sale. Kingsport had the most land for sale. Manufacturing and related services are the largest economic sectors in Sullivan County. Sullivan County is Tennessee's 56th biggest county (429 square miles). It's located in the Eastern Tennessee region of the state.