The run is set along the original Western States Trail starting at Squaw Valley, California and ending in Auburn, California, covering a staggering 160km. The trail climbs from the Squaw Valley floor (6200feet above sea level) to Emigrant Pass (8750feet above sea level) a climb of roughly 2550 vertical feet in the first 7.2km. From the pass, following the original trails used by the gold and silver miners of the 1850’s, climbing another 15 540 feet and descending 22 970 feet before reaching Auburn. Most of the trail passes through remote and rugged territory, accessible only to hikers, horses and helicopters.

The race originated in 1955 when the late Wendell T. Robie rode the Western States Trail from Squaw Valley to Auburn with 5 other horsemen, to prove that horses could cover 160km in one day; officially starting the annual Western States Trail Ride. In 1974, Gordy Ashleigh joined the ride to see if he could complete the course on foot – 23hrs42min later Gordy arrived in Auburn proving runners could run the 160km in less than one day.