AC100 in Plain English

Angeles Crest 100 is a point-to-point 100-miler through the San Gabriel Mountains. Big early climbs, hot canyons, tight cutoffs, and tricky logistics make it one of the tougher hundreds in the U.S. This guide is meant to be your first stop if you’re even thinking about running it.

Want shorter tactical reads? Use the Free Guides hub.

1. What makes AC100 different?

Point-to-point: You start in Wrightwood and finish in Altadena, with no loop or out-and-back to fall back on.
Early climbing: You hit big elevation early, when it’s easy to go too hard and burn your legs.
Heat + exposure: Canyons and ridges can be brutally hot even when LA feels reasonable.
Night stretch: Most runners spend a long, mentally heavy stretch in the dark.
Logistics: Crew access is limited, parking is tight, and the Solo division changes how you plan.

2. Basic stats at a glance

Distance: ~100.2 miles
Total climb: ~20,000 ft
Cutoff: 33 hours
Start: Wrightwood, CA
Finish: Altadena, CA
Time of year: Late summer (heat, fire smoke, and storms can all be factors)

3. Who is AC100 a good fit for?

In general, AC100 is a good fit if:

You’ve finished at least one 50-mile or 100k trail race.
You’re willing to train for sustained climbs and long descents, not just flat mileage.
You can commit to several months of consistent training, with some weekend time in the mountains.
You’re okay with a race where heat, altitude, and logistics can all be as hard as the miles.

It’s probably not the right first 100 if you hate technical trails, heat, or heights, or if you can’t realistically get any steep or trail training.

4. Lottery, qualifiers, and trail work (high level)

This is a summary only – always check the official AC100 site for current rules.

Lottery & qualifiers: You typically need a qualifying ultra and you enter through a lottery system.
Trail work: Runners are expected to complete a set number of hours of trail work before race day.
Solo vs. crewed: You choose whether to run in the Solo division or with crew/pacers, and that affects your planning.

On this site I’ll keep a running, plain-English explanation of how these rules work this year, plus examples of how past runners have satisfied them.

5. Your next steps

Decide if AC100 is a realistic goal in the next 1–3 years.
Pick a qualifying race and rough timeline.
Start building mountain fitness and downhill strength.
Join the AC100 Intel List so you get updates on rule changes and new guides.

When you’re ready, head back to the homepage and dive into: