

The idea for the race was inspired upon hearing about the 1977 escape of James Earl Ray, the assassin of Martin Luther King Jr., from nearby Brushy Mountain State Penitentiary. The Barkley course was the brain child of Gary " Lazarus Lake" Cantrell and Karl Henn (Raw Dog). The race is limited to a 60-hour period from the start of the first loop, and takes place in March or early April of each year. The course, which varies from year to year, consists of five loops of the 20+ mile, off-trail course for a total of 100 miles (160 km).

The Barkley Marathons is an ultramarathon trail race held each year in Frozen Head State Park in Morgan County, Tennessee.
