The Western Slam of Ultrarunning

Tackle 4 challenging 100-mile ultras in the Western USA.

Greg Heil


Taken on the Leadville course in the fall

by Greg Heil

Taken on the Leadville course in the fall

by Greg Heil




Trail running continues to explode in popularity, and while shorter races will always be the most easily-accessible, participation in ultra trail races continues to soar. At the extreme end of the sport is the 100-mile distance. Despite the incredible difficulty, the idea of racing 100 miles on foot to truly test your mettle against the mountains and your fellow man captures the imagination of thousands of runners.

While there are plenty of 100-mile races to go around, a fabled few are so revered in the collective trail running consciousness that they've come to embody a bonafide bucket list. Unlike some road marathons that can accommodate thousands of participants, trail races have to cap the number of participants much much lower (sometimes below 100), meaning that to get into the most popular races, you must either qualify, enter a lottery, or both.

Some of the most coveted 100-mile races have been rounded up into various "grand slams" where ultra runners can seek to knock a specific race itinerary out of the park. One of the most popular slams is the Western Slam, outlined in this guidebook.

The Western Slam covers four incredibly difficult 100-mile endurance runs, and unlike some of the slams that allow substitutions or options, runners have to complete all four of these specific races in order to complete the slam. From east to west, they are:

-Leadville Trail 100
-Wasatch 100
-Western States 100
-Angeles Crest 100



Wasatch 100

The run stretches from East Mountain Wilderness Park, Utah to Soldier Hollow, Utah and covers some of the most beautiful scenery the Wasatch Mountains have to offer. There is a cumulative gain of approximately 24,000 feet, as well as a cumulative loss of approximately 23,300 feet throughout the course.

Western States 100

The full route of the Western States 100 Ultra Marathon from Squaw Valley to Auburn in one day. Join the Western States Strava club here:

Angeles Crest 100

Cross the San Gabriel mountain range in one single push during the Angeles Crest 100.