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.
C-reactive protein (CRP) is an annular (ring-shaped), pentameric protein found in blood plasma, whose levels rise in response to inflammation. It is an acute-phase protein of hepatic origin that increases following interleukin-6 secretion by macrophages and T cells.RP is a general marker for inflammation and infection, so it can be used as a very rough proxy for heart disease risk. Since many things can cause elevated CRP, this is not a very specific prognostic indicator.