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.
CPK stands for creatine phosphokinase. Itâs an enzyme found in high concentrations in muscles, where it facilitates muscle contraction. CPK is also called creatine kinase or CK. In a rare condition called rhabdomyolysis, extreme muscle breakdown floods the blood with CPK and other chemicals in muscle cells.