According to the U.S. Census Bureau, the county has a total area of 685 square miles (1,770 km2), of which 681 square miles (1,760 km2) is land and 3.8 square miles (9.8 km2) (0.6%) is water. It is the fourth-largest county in Tennessee by area. The county is located atop the Cumberland Plateau.
Revenue passenger kilometres (RPK) is a measure of the volume of passengers carried by an airline. A revenue passenger-kilometre is flown when a revenue passenger is carried one kilometre. A passenger for whose transportation an air carrier receives commercial remuneration is called a revenue passenger.
Most notably, the RPK has a heavier and longer barrel than an AKM. This allows the RPK to fire for extended periods of time without major loss in accuracy due to the barrel heating up. The chrome-lined barrel is permanently fixed to the receiver, and cannot be replaced in the field.