In terms of average elevation, Johnson County is one of the highest counties (if not the highest) in Tennessee. The county is home to the two highest communities in the state: Trade, at , and Shady Valley, at . Mountain City is the highest incorporated city in Tennessee, at . The highest place in Johnson County is Snake Mountain's lower peak, (near the North Carolina state line), at 5,518 feet (1,682 m). The lowest point in the county is Watauga Lake, at an elevation of .
