
First published on June 30, 2015. Updated June 18, 2025.
August 2nd runners from near and far will gather in a small parking lot in Wrightwood, California, to start the Angeles Crest 100 Mile Endurance Run (AC100). Begun in 1986, the AC100 is one of the original five 100-mile U.S. endurance races. It has endured fires, floods, the Covid-19 pandemic, and changing trail restrictions.
There’s a tradition of running grueling endurance races in the San Gabriel Mountains. The Big Pines Trail Marathon was one of the first organized mountain ultramarathons in the U.S. First run in August 1934, its course used some of the same trails that AC100 runners enjoy today.
The AC100 is not like a road marathon. It is an entirely different kind of running event and an entirely different kind of running experience. The 2025 L.A. Marathon had about 26,000 participants. About 1/100th of that number — around 250 runners — are expected to start the AC100.

The race begins at 5:00 a.m. Runners work their way through the streets of Wrightwood by headlamp to the start of the Acorn Trail, dawn breaking as they work up toward the PCT. Sunrise finds them above 8000 feet, reveling in the spectacular views from Blue Ridge.
Even at this early stage of the race, the field is already becoming dispersed. By the time runners reach Inspiration Point, nine miles into the run, there will be an hour spread between the first and last runner. Unlike a road marathon, much of the time a runner in the AC100 will be alone.
Because of the devastating Eaton Fire, this year’s course will be the same as in 2022 — a challenging run from Wrightwood to Shortcut Saddle (51.3 miles) and back.
Of course it’s the “back” part that increases the difficulty. Going back to Wrightwood means returning to the high country of the San Gabriels and the high point of the course — Mt. Baden-Powell. As a result, more of the course will be at higher elevation. According to Google Earth, the average elevation of recent point-to-point AC100 courses have been around 5100′-5300′. The elevation of this year’s course averages about 6900′. Because of the increased difficulty, cutoff times have been adjusted and the overall time to complete the course has been increased to 36 hours.
This elevation profile for the 2025 AC100 course was created using a GPX file of a runner in the 2022 race. The elevation profile was corrected using 3DEP 1-meter Lidar-based DEMs and a conservative elevation data smoothing setting. The cumulative elevation gain/loss is ESTIMATED to be around 20,600′. This is based on estimates using SportTracks, Strava, and Google. Placemark locations, mileages, and elevation gains and losses are approximate.
The elevation profile can be downloaded from the Course Overview page on the AC100 website.

In addition, here is an interactive, high resolution, 3D-terrain map of the 2025 Angeles Crest 100 Mile Race. It is based on the same GPX file as the elevation profile. The view is initially zoomed in on the climb up Mt. Baden-Powell. To change the view, use the control on the upper right side of the screen. Track and placename locations are approximate and subject to errors.

See the AC100 website for official information and details.