About the race
The Western States Endurance Run, usually called Western States or WSER, is a 100.2-mile trail race through California's Sierra Nevada from Olympic Valley to Auburn. The organiser calls it the world's oldest 100-mile trail race, and the Western States Endurance Run Foundation administers it.
History
The trail was first covered on foot in 1972, when twenty soldiers from Fort Riley, Kansas, set off a day ahead of the Tevis Cup horse ride; seven finished. In 1974 Gordy Ainsleigh became the first to complete it in under 24 hours. The first official race was in 1977 with sixteen starters, and three finishers who stayed in the field led to the first sub-30-hour awards. A lottery for entry was introduced in 1981. The 2026 race was the 53rd and produced new course records.
The course
The race starts at the base of Palisades Tahoe in Olympic Valley, near the site of the 1960 Winter Olympics. Runners climb almost at once to Emigrant Pass, cross the Granite Chief Wilderness and the Foresthill Divide, drop into the American River canyon and cross the Middle Fork of the river. The finish is on the track at Placer High School in Auburn. Over the whole distance the organiser says runners climb more than 18,000 feet and descend nearly 23,000 feet. The course has followed the same route since 1986.
The 2027 race
The organiser lists the 2027 race for 26 and 27 June 2027. The 2026 race started at 5 am on the Saturday.
Entry basics
Entry is by lottery. The organiser lists the 2027 application window as 1 to 21 November, with the drawing on 5 December. Its entry pages also cover qualifying races, automatic entries, special consideration, deferrals and wait lists. The run awards a silver buckle for finishing in under 24 hours and a bronze buckle for under 30 hours.
Where to watch
Much of the trail is reachable only on foot, by horse or by helicopter, so most spectators see the start in Olympic Valley or the finish at Placer High School in Auburn. The organiser has race-week pages for crews, pacers and the finish line, as well as a live webcast.
Weather
The course crosses high country and deep canyons, so conditions can differ enormously from start to finish. Wikipedia notes that snow can linger on the passes while the canyons can be very hot, and the organiser keeps a weather history page. Late June weather varies from year to year.
SourcesWestern States Endurance Run home · Wikipedia: Western States Endurance Run