The legendary 100-mile run started back in 1986. One of the original five 100 milers. AC100 has strived to keep the race’s original point-to-point course from Wrightwood to Altadena largely intact while preserving its level of difficulty. It’s one of only 6 point-to-point 100-mile runs in the country. You’ll traverse 100 miles of San Gabriel mountains from elevations of 1,135 to 9,300 feet.

The 34th Annual AC100 will be on August 3, 2024

Invitations are available for the 2024 Race Waitlist

How to enter
2024 AC100

  • The only way to enter 2024 AC100 is through the Waitlist.
  • To sign up for the Waitlist, you must have an UltraSignup account with a valid payment method.
  • If a runner drops, a runner from the Waitlist will be invited to fill that spot. You will have the option to accept or decline before your credit card is charged.
  • All new entrants must run a 50+ Mile Race between July 31, 2022 and July 13, 2024. The result of your qualifying run must be published in a magazine like Ultra Running or on UltraSignup’s website. 
  • Refund Policy: 50% up until March 1, 2024 and 25% up until June 1, 2024.
  • We will continue to add Waitlist runners to the race until June 1, 2024.
  • All runners in the race are required to complete and submit Trail Work between April 1, 2023, to July 13, 2024. Runners who do not complete the Trail Work, will not be allowed to start the Race.
  • Signing up for the SOLO division means that you will have no pacer(s) and no crew support during the race.  Switching divisions is not permitted after signup.
2019 AC100 Champ Melissa Danehey. Photo- Kaori Photo