Described as "The Race That Eats Its Young", it is known for its extreme difficulty, purposefully difficult application process, and many strange traditions, having been completed only 26 times by 20 runners since 1995.

The race is limited to a 60-hour period from the start of the first loop, and takes place on the weekend nearest April Fools' Day each year.

The Barkley course was the brainchild of Gary "Lazarus Lake" Cantrell and Karl "Raw Dog" Henn,[1] who often hiked Frozen Head together.

[2] The idea for the race was inspired by the 1977 escape of James Earl Ray who was convicted for the assassination of Martin Luther King Jr., from nearby Brushy Mountain State Penitentiary.

[6] For the early years, the Barkley course was approximately 50–55 miles (80–89 km), with about 25,000–27,000 feet (7,600–8,200 m) of climbing,[7] in a 24-hour time limit.

[8] That year, Mark Williams of the United Kingdom became the first participant to finish the full longer version of the Barkley Marathons with a time of 59:28:48.

[8] In 2009, Brushy Mountain State Penitentiary closed, allowing it to eventually become part of the Barkley course including a tunnel under the prison and a pass by the wall through which Ray escaped.

[2] In 2017, Gary Robbins of North Vancouver, British Columbia, reached the finishing gate a mere six seconds after the 60-hour cut-off, almost becoming the 16th runner ever to complete the Barkley.

[13] Previous women to have completed the 3-loop 'Fun Run' are Suzi Thibeault (1991, 1994), Nancy Hamilton (1991, 1993), Sue Johnston (2000, 2001) and Beverley Anderson-Abbs (2012, 2013).

[2] Registration and application for the race is purposefully difficult; Cantrell has stated that "anything that makes it more mentally stressful for the runners is good."

Requirements and times to submit an entry application are a closely guarded secret with no details advertised publicly and no official website.

These have included questions such as "What is the most important vegetable group?,"[2] "What will be the 119th element on the periodic table?," and "Write the Gettysburg Address in Sawveh.

[2] If accepted, an entrant receives a "letter of condolence" from Cantrell's pseudonym Lazarus Lake which warns them that they have a "very bad thing waiting."

Cantrell also picks at least one "sacrificial virgin,"[2] or "human sacrifice,"[17] who, based on their answers in the essay and test,[10] he believes has no chance of finishing the race.

[17] Upon arriving, first-time Barkley runners, known as virgins, are required to bring a license plate from their state or country as part of the entrance fee,[2] which are hung from the trees each year as mementos.

[citation needed] Prior finishers of the marathon who return to run again must submit a pack of Camel cigarettes as part of the registration fee.

Traditionally the date of the race is a closely guarded secret, however in 2024 it was reported as taking place on the weekend nearest April Fools' Day.

Prior to Jasmin Paris's finish in 2024, as well as her 2023 performance (getting to the 9th book on the 4th lap), the best women's achievement was Sue Johnston's 66 miles (106 km) in 2001.