Western States Endurance Run
Annual ultramarathon in California
The Western States Endurance Run, known commonly as the Western States 100 or Western States, is a 100.2-mile (161 km) ultramarathon that takes place on California's Sierra Nevada Mountains trails each year on the last full weekend of June. Western States is one of the most competitive ultramarathons in the United States, and is administered by the nonprofit Western States Endurance Run Foundation.
The Western States 100 is one of the five 100-mile races that comprise the Grand Slam of Ultrarunning, which also includes the Old Dominion 100 in Virginia, the Vermont 100 Mile Endurance Run, the Wasatch Front 100 Mile Endurance Run in Utah, and the Leadville Trail 100 in Colorado. One of the more prestigious ultramarathons in the world, it is a qualifier for the UTMB World Series, although the UTMB organization has a major competing race in the same area with a similar course, called "Canyons Endurance Runs by UTMB".
History
The course was first attempted on foot by twenty soldiers from Fort Riley, Kansas during the 1972 Tevis Cup horse ride event. Because the Tevis Cup imposed a 24-hour time limit, the soldiers started one day before the horses. Seven completed the 100.2 miles, and it was subsequently reported as the first "Auburn Endurance March". In 1974, Gordy Ainsleigh became the first to complete the course in under 24 hours, arriving in Auburn in twenty-three hours and forty-two minutes. In 1976, Ken “Cowman” Shirk became the second to complete the distance, though 30 minutes over the 24-hour mark.
Sixteen runners signed up for the first official Western States Endurance Run in 1977, held in conjunction with the Tevis Cup.
The public source identifies “Western States Endurance Run” as annual ultramarathon in California. This brief keeps that definition visible, then builds a research path around Western, States and Endurance.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Aug 27, 2026. The linked authority identifier is Q221853. VIAF identifies the subject as 14160208398848620643. 2 of 3 selected statements include explicit references; 1 carry qualifiers and 0 use preferred rank. The first chronological checks are 1972, 1974, 1976 and 1977.
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This entry incorporates text from “Western States Endurance Run” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.