The Western Slam of Ultrarunning

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

Sources:
LeadvilleRaceSeries.com
Wikipedia.org
WSER.org