Johnson County's Location Johnson County's Location Johnson County is located in the extreme northeastern corner of Tennessee. It is shaped like an ancient arrowhead pointing in a northeastern direction. Virginia is to the north and North Carolina is to the east of Johnson County.
Mountain City is the county seat.
It is located in the center of the county in a large valley between the Iron and Stone Mountain Ranges. The Doe and Dry Run Ranges are to the southwest of Mountain City, and the Forge Mountain Range is to the northeast. The land of Johnson County varies between flat valleys and steep mountains. The county has 249,600 acres or 273 square miles of land. The extreme dimension of Johnson County is 24 miles.