Ever wonder how to tackle the Western States 100? Many runners struggle to understand this famous ultramarathon, its rich history, and how to qualify. And having just entered the lottery for the second time, at first, the details can feel overwhelming. But with the right guide, you’ll be prepared for the journey.

The Western States 100 is the oldest 100-mile trail race in the world, beginning in Olympic Valley, California, and ending in Auburn. The 100.2-mile course is both treacherous and scenic, challenging even the most seasoned runners.
This blog will break down all you need to know about the Western States 100, including course details, history, and entry tips. Keep reading—your ultimate guide starts here!
Key Takeaways
- Oldest Ultra: The Western States 100, established as an ultramarathon in 1974, originated as a horse race in 1955. Its first foot completion by Gordon Ainsleigh marked its transformation.
- Challenging Course: Runners face an intense course with over 18,000 feet of elevation gain and nearly 23,000 feet of descent, from Olympic Valley to Auburn, California.
- Competitive Entry: Qualifying involves completing specific ultra races within a set period; entry is determined by a highly competitive lottery system, with around 10,000 applicants annually.
- Comprehensive Support: Aid stations provide critical hydration, nutrition, and medical support, including major medical checkpoints staffed by approximately 50 physicians and 75 nurses.
- Notable Records: Jim Walmsley’s men’s overall record of 14:09:28 in 2019 and Courtney Dauwalter’s women’s record of 15:29:33 in 2023 exemplify the extraordinary efforts of top finishers.
The Western States 100 Race History
The Western States 100 has a rich history that dates back to its roots as a horseback endurance race. In the 1950s, the trail challenged riders and their horses, and by the 1970s, it evolved into the world-renowned ultramarathon it is today.
Origins as a Horse Race

The Western States Endurance Run traces its roots to the Tevis Cup, a 100-mile horseback ride across the Sierra Nevada mountains, first organized in 1955. The Tevis Cup challenged riders to navigate steep canyons, rugged trails, and high altitudes from Lake Tahoe to Auburn, California, all within a strict 24-hour time limit. This endurance event quickly gained popularity as one of the most grueling tests of both horse and rider.
For nearly two decades, only horses and riders dared to complete the Western States Trail. But in 1974, a pivotal moment changed the race’s course forever.
Gordon “Gordy” Ainsleigh’s Historic Run
In 1974, Gordon Ainsleigh, an experienced Tevis Cup rider, faced an unexpected setback: his horse was injured shortly before the race. Rather than skip the event, Ainsleigh chose to tackle the 100-mile trail on foot, intending to finish within the 24-hour limit set for horseback riders. Against all odds, Ainsleigh completed the journey in 23 hours and 42 minutes, proving that a person could run the challenging course and inspiring what would become the Western States Endurance Run.
This monumental feat sparked a new interest in human endurance on the trail. Runners began to challenge themselves in subsequent years, marking a shift from horseback to footrace.
Founding of the Western States Endurance Run
By 1977, the Western States Endurance Run officially opened as an organized ultramarathon. Sixteen runners gathered to take on the course, but only three succeeded in finishing the race. This inaugural race established the Western States 100 as a formidable test of endurance and resilience.
The organizers drew on the structure of the Tevis Cup, incorporating aid stations and support teams to help runners tackle the rugged terrain and unpredictable weather conditions. Over the years, safety protocols and logistical support expanded, ensuring runners received the necessary aid to endure the grueling journey from Olympic Valley to Auburn.
Notable Milestones and Key Moments
- 1974: Gordy Ainsleigh completes the trail on foot, inspiring the concept of a human endurance race.
- 1977: The first official Western States Endurance Run is held, with sixteen participants and three finishers.
- 1981: A lottery system is introduced as the race gains popularity, allowing organizers to fairly select participants for the limited spots.
- 1986: The course is permanently established, creating a consistent route for all runners.
- 1990s: The race garners international attention, attracting elite ultrarunners and solidifying its place as a premier event in the ultrarunning community.
- 50th Anniversary (2023): Western States celebrates 50 years of ultrarunning excellence, with 328 finishers tying the 2010 record for most participants to cross the finish line.
Evolution of Race Culture and Legacy
Over the decades, the Western States 100 has grown into one of the most prestigious ultramarathons worldwide. It serves as a proving ground for ultrarunners, offering a unique blend of rugged natural beauty, historical significance, and a profound test of physical and mental endurance. With its 100-mile course and intense elevation profile, the race is often seen as the ultimate benchmark for ultrarunners.
Course Information

The Western States 100 spans from Olympic Valley to Auburn, California, covering a scenic yet grueling 100.2 miles. The route includes rugged trails, steep climbs, and breathtaking mountain vistas.
Starting Point and Finish Line Details
- Start: Olympic Valley at 5:00 a.m. on the last Saturday in June.
- Finish: Placer High School in Auburn, CA.
- Many runners describe the finish line as the culmination of a dream, marking a personal triumph over this iconic course.
Key Features of the Trail
- Distance: 100.2 miles from Squaw Valley to Auburn, CA.
- Elevation Gain and Loss: Over 18,000 feet of ascent and nearly 23,000 feet of descent.
- Notable Passes: Emigrant Pass at 8,750 feet within the first few miles.
- Highlights: Granite Chief Wilderness with panoramic mountain views, historic Gold Rush trails, and several steep canyons, including the Middle Fork of the American River canyon.
- Diverse Landscapes: Runners experience high-altitude forests, river trails, and rocky canyon terrain.
- Aid Stations: Strategically placed throughout the trail to offer hydration, nutrition, and medical support.
Elevation Profile
Starting at Squaw Valley at an elevation of 6,000 feet, the course reaches its highest point at around 8,750 feet. The elevation gain of 18,090 feet tests runners with continuous climbs and descents across the Sierra Nevada, adding to the race’s reputation as a challenging and iconic event.
How to Qualify for the Western States 100
Qualifying for this race requires completing a designated ultra race, typically of at least 100 kilometers, within a specific period. Due to the high demand, a lottery system is used to select participants.
Official List of Qualifying Races
Qualifying Races and Standards
Runners must complete an approved qualifying race within the designated period to enter the lottery. The qualifying period for the 2024 race was November 7, 2022, to November 5, 2023. Over 200 races meet these qualification standards, each demanding rigorous endurance.
Lottery System and Entry Process
Approximately 10,000 hopefuls enter the Western States 100 lottery each year, competing for one of 375 spots. Register by November 21, 2024, to join the lottery. Each entry is weighted by how many years you’ve entered, following the formula 2(N−1)2^{(N-1)}2(N−1), where N represents the number of consecutive years entered. The drawing takes place the first Saturday in December at Placer High School in Auburn, CA.
Link to Western States 100 Entry Process Page
Race Features
The Western States 100 offers aid stations, food, hydration, and medical support to assist runners along the demanding course.
Aid Stations and Support
- 20 Aid Stations: Hydration, snacks, and essential supplies are available throughout the trail.
- Medical Support: 10 major medical checkpoints with on-site medical teams.
- Hydration Options: Water, GU Hydration Drink Tabs, and energy gels are provided.
- Nutrition: Quick snacks, including fruits and cookies, are available to keep runners fueled.
- Reusable Cups: Participants must use reusable cups to minimize waste.
Cut-off Times and Race Rules
- 30-Hour Limit: Runners have up to 30 hours to complete the course.
- Aid Station Cut-offs: Strict times at each aid station.
- Qualifying Requirement: Only runners who have completed a qualifying race can enter the lottery.
- Virtual Races Exclusion: Virtual events do not count toward qualifying.
- Completion Rules: Runners must cross the finish within 30 hours for an official completion.
Western States 100 Course Records

| Category | Athlete | Record Time | Year |
|---|---|---|---|
| Men’s Overall | Jim Walmsley | 14:09:28 | 2019 |
| Women’s Overall | Courtney Dauwalter | 15:29:33 | 2023 |
| Masters Male | Tyler Green | 15:05:39 | 2024 |
| Masters Female (40-49) | Ida Nilsson | 16:56:52 | 2024 |
| 18-29 Female | Emily Hawgood | 16:48:43 | 2024 |
| 50-59 Female | Meghan Canfield | 18:50:19 | 2011 |
Conclusion
The Western States 100 is a historic test of endurance and skill. This race challenges runners across 100.2 miles of rugged terrain, pushing them to their limits. Qualifying requires dedication through ultrarunning and a competitive lottery, with aid stations providing crucial support. Completing this race within 24 or 30 hours is a celebrated achievement.
Ready to conquer the Western States 100? With the right preparation and mindset, you too can join the ranks of those who have crossed this legendary finish line.
FAQs
1. What is the Western States 100 course like?
The course spans rugged terrain, including steep climbs and descents, through forests, rivers, and mountainous areas over a 100-mile distance.
2. How did the Western States 100 originate?
The race started in 1974 when Gordy Ainsleigh ran alongside horses in the Tevis Cup Ride, completing it on foot and leading to the creation of the ultramarathon.
3. What are the qualifications for participating in the Western States 100?
To qualify, runners must complete an approved race within a set timeframe and enter a lottery system.
4. Where can I find historical race information?
Historical data on past races, records, and performances can be found on the official Western States Endurance Run website and related publications.








