Western States 100: The Oldest 100-Mile Trail Race
The Western States Endurance Run (WSER) is the oldest 100-mile trail race in the world — 100 miles from Squaw Valley (Olympic Valley) to Auburn, California, through the Sierra Nevada, with ~5,500 m of climb and a 30-hour cut-off.
It is one of the three races of the "Western Slam" and the historical benchmark of American ultrarunning. Entry is via a lottery restricted to runners who have completed a qualifying race.
Date verification: Dates for the next edition have not yet been officially announced. Western States 100 is traditionally held in late June — check the official website for confirmed dates.
Distance categories: 100 miles (~161 km) · 30-hour cut-off
Elevation gain: ~5,500 m ascent / ~6,700 m descent
Entry: Entry via a lottery, restricted to runners who have completed a qualifying 100-mile/100km race within the qualifying window. See the official website for current qualifying races and lottery rules.
The Course and Qualification
The course follows historic trails from the Sierra Nevada high country to the foothills, crossing canyons and the American River. Heat in the canyons is the defining challenge — afternoon temperatures routinely exceed 38 °C.
Entry requires completing a qualifying race (a 100-mile or specified 100km) within the qualifying window, then entering a lottery with roughly 1-in-7 odds. See the official WSER website for current qualifying races and rules.
Frequently asked questions
- How far is the Western States 100? 100 miles (~161 km) from Squaw Valley to Auburn, California, with about 5,500 m of climb and a 30-hour cut-off.
- How do I enter Western States? Complete a qualifying 100-mile/100km race within the qualifying window, then enter a lottery with roughly 1-in-7 odds. See the official website for current qualifying races.
- When is Western States 100? Traditionally held in late June. Dates for the next edition have not yet been officially announced — check the official website.
Morocco Trekking — Mountain endurance trekking in a different range — the Atlas Mountains.