Saturday, Oct 2, 2027

Angeles Crest 100 Mile Endurance Run

Loma Alta Park

Altadena, CA • 100 Miler, 100K

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37TH ANNUAL
ANGELES CREST 100 MILE ENDURANCE RUN
Saturday, October 2, 2027
Loma Alta Park, Altadena, California

The Angeles Crest 100 Mile Endurance Run began in 1986 and is one of the original five 100-mile endurance runs in the United States.

The 37th Annual AC100 will take place on Saturday, October 2, 2027. The event will return to the revised course through the San Gabriel Mountains that was introduced in 2026, beginning and ending at Loma Alta Park in Altadena.

Runners will encounter steep climbs, rocky trails, remote mountain terrain, and approximately 100 miles of demanding conditions. AC100 is not easy, but every finisher knows the journey is worth it.

For the first time, race weekend will also include an Angeles Crest 100K. Both races will take place on the same day.

Training runs and trail workdays are an important part of the AC100 experience. They give runners an opportunity to prepare for the course, build friendships, and give back to the trails.

Lottery Process

The 2027 AC100 lottery opens October 12, 2026.

All runners may enter the lottery.
Approximately 210 positions will be available through the lottery. Remaining positions are reserved for volunteers, sponsors, Sterling Silver Ticket recipients, and other race commitments.
Your card will only be charged if you are selected.
Runners who are not selected will be placed on the waitlist in lottery order.
Previous AC100 finishes, prior unsuccessful lottery attempts, volunteer service, and entry in the Solo division may increase selection odds.
The SOLO division does not allow pacers or crew.
Division changes will not be permitted after registration.

Lottery opens: October 12, 2026
Lottery closes: October 26, 2026
Entrants & waitlist announced: Friday, October 30, 2026

Elevation profile for the 2026 AC100 course - 100.8 miles from Loma Alta Park to Mt. Hillyer and back, with approximately 20,000 feet of elevation gain.

2026 AC100 Course Map - 100.8-mile loop starting and finishing at Loma Alta Park in Altadena.

2027 Refund Policy

50% refund through May 1, 2027
25% refund through September 1, 2027

No refunds after September 1, 2027.

Entries are not transferable.
Deferrals and rollovers are not permitted unless the race is canceled or AC100 announces an exception.

Contact AC100 directly to request a refund.

Entry Requirements

Qualifying Race

100-mile entrants must complete an official race of 50 miles or longer between January 1, 2026, and September 2, 2027.

Results must be published through UltraSignup, UltraRunning, or another official results provider. Virtual races do not qualify.

You may enter the lottery before completing your qualifying race.

Trail Work

All 100-mile entrants must complete eight hours of trail work by September 2, 2027.

Entrants living in California south of Fresno must complete their trail work with AC100 in the Angeles National Forest.

Entrants living north of Fresno, outside California, or outside the United States may complete equivalent trail work with a local trail organization or race.

The 2027 AC100

The 2027 AC100 will use the revised loop course introduced in 2026, beginning and ending at Loma Alta Park in Altadena.

The 100-mile course travels through Clear Creek, Josephine Peak, Red Box, Newcomb, Shortcut, Chilao, and Mt. Hillyer. It returns through Chilao, Shortcut, and Newcomb before continuing through Chantry Flats, Mt. Wilson, Sam Merrill, and Millard to the finish at Loma Alta Park.

Distance: Approximately 100.8 miles

Elevation gain: Approximately 20,000 feet

Time limit: 33 hours

Start and finish: Loma Alta Park, Altadena

Course details remain subject to permits, trail conditions, fire closures, weather, and other safety considerations.

100K Course

The Angeles Crest 100K is a separate race held on the same day as the AC100 100 Mile Endurance Run. The 100K begins at 7:00 AM and starts and finishes at Loma Alta Park in Altadena.

The estimated course travels through Clear Creek, Josephine Peak, Red Box, Newcomb, Chantry Flats, Mt. Wilson, Sam Merrill, and Millard before returning to Loma Alta Park.

Checkpoint	Est. mileage
Loma Alta Park start	0.0
Clear Creek	11.2
Josephine Peak	15.3
Red Box	24.6
Newcomb	33.2
Chantry Flats	39.5
Mt. Wilson	45.6
Sam Merrill	51.2
Millard	57.2
Loma Alta Park finish	61.6

Estimated distance: 61.6 miles
Estimated elevation gain: 13,271 feet
Start time: 7:00 AM
Time limit: 18.5 hours
Final cutoff: 1:30 AM Sunday

Final checkpoint mileage, aid-station locations, and cutoff times are subject to confirmation.

FINISHER AWARDS

Finishing AC100 is an outstanding accomplishment. Every official finisher completing the race within the 33-hour cutoff will receive:

An official AC100 finisher shirt
An AC100 bronze finisher medallion
The appropriate AC100 finisher buckle

The awards ceremony gives runners, families, volunteers, and crews an opportunity to recognize every finisher.

2026 course changes

Due to current road and trail closures and the effects of recent fires, the 2026 AC100 will use a new 100.8-mile loop course starting and finishing at Loma Alta Park in Altadena.

Runners will travel through Clear Creek, Josephine Peak, Red Box, Newcomb, Shortcut and Chilao before reaching Mt. Hillyer. The course then returns through Chilao, Shortcut and Newcomb before continuing through Chantry Flats, Mt. Wilson, Sam Merrill and Millard to the finish at Loma Alta Park.

the buckles

All Finishers get a Finisher Plaque with their Name and Finish Time engraved on it as they cross the Finish Line.

All Finishers get a Finisher T-shirt. The Solo Finisher gets Solo Finisher T-shirt.

Runners who cross the Finish Line in less than 24 hours receive the Solid Sterling Silver Buckle.

All Runners finishing between 24 and 24:59:59 hours receive the Solid Bronze Second Sunrise Ram Buckle.

Any Runner who completes the race between 25:00 and 33:00 hours is awarded with the 33 Hour Solid Bronze Ram Buckle.

Solo Finisher who finish in Sub 24 hours receive the 24-Hour Solo Solid Sterling Silver Buckle.

All Solo Finishers between 25:00 and 33:00 receive the 33 hour Solo Solid Bronze Ram Buckle.

Any female runner who breaks the existing female course record of 21:04:18 receive the 24-Hour Solid Sterling Silver / 14K Gold Rejoice Buckle.

Any runner who breaks the existing traditional-course record of 17:35:48, set by Jim O’Brien in 1989, receives the 24-Hour Solid Sterling Silver buckle plated in 14K Gold. The record has stood for 37 years, and only four other runners have ever broken the 19-hour mark on the traditional course. Both men and women are eligible for this award. The 2026 loop course is not eligible for the traditional course-record award.

The Trophies

The Ram: Presented to the overall male and female winners.
The Cougar: Presented to the first male and female Solo finishers. If an overall winner competed in the Solo division, The Cougar will be presented to the next eligible Solo finisher.
The Elk: Presented to runners completing 10 AC100 races.
The Eagle: Presented to runners completing 10 consecutive AC100 races.
The Grizzly: Presented to runners completing 20 consecutive AC100 races.