FOURmidable Logo

FOURmidable

Sat, Feb 13, 2027
In 94 days
Auburn, CA
855 Pacific ave

On this date: rain 2 of the last 10 years

2026

33–49°F

dry

2025

40–61°F

dry

2024

46–59°F

rain

2023

39–62°F

dry

2022

46–60°F

dry

2021

41–53°F

dry

2020

43–64°F

dry

2019

36–49°F

dry

2018

28–47°F

dry

2017

50–54°F

rain

Best months to race in California →

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About this race

FOURmidable Trail Run (50K | 35K | Half Marathon+ | 13K)

Presented by SingleTrack Running

Location: Auburn Overlook Park — 855 Pacific Ave, Auburn, CA 95603

Are you ready to test your grit on one of Northern California's premier trail challenges? Hosted in the endurance capital of the world, the FOURmidable Trail Run takes runners through the rugged, scenic canyon trails of the Auburn and Cool areas.

Featuring less than one mile of pavement across all distances, this event treats you to singletrack trails, river canyon views, and the infamous climbs that give the race its name.

The Four Climbs

The signature 50K course packs over 6,000 feet of cumulative elevation gain, headlined by the "FOUR" formidable climbs:

  • Cardiac Hill
  • K2 (aka Training Hill)
  • Knickerbocker (Old Auburn Dam Site)
  • Overlook Hill

Whether you take on the full 50K ultra or choose the 35K, Half Marathon+ (13.2 mi), or 13K, you will experience the best singletrack Auburn has to offer.

Race Schedule & Start Times

All distances run on race day.

Distance Start Time 50K 8:00 AM 35K 8:15 AM Half Marathon+ (13.2 mi) 8:30 AM 13K 9:00 AM

What's Included

  • Custom Swag & Bibs: SingleTrack Running takes pride in quality, practical swag designed to celebrate your finish without cluttering your closet.
  • Fully Stocked Aid Stations: Staffed by experienced trail volunteers ready to help refuel and hydrate you quickly. Stations include water, electrolyte drink, gels, soda, boiled potatoes, candy, salt tabs, and more.
  • Post-Race Celebration: Finish at Overlook Park with plenty of hot food, drinks, and trail camaraderie.

Important Event Logistics

1. Cupless Racing

In an effort to keep trails clean and minimize waste, FOURmidable is a 100% cupless event.

  • Every runner must carry a handheld bottle, hydration pack, or reusable collapsible cup.
  • Paper cups will not be provided at aid stations. Collapsible cups will be available for purchase on-site, or you can bring your own.

2. Packet Pick-Up

  • Early Pick-Up (Recommended): Friday (day before the race) from 3:00 PM – 6:00 PM at the Start/Finish area (Auburn Overlook Park).
  • Race Morning: Available at Overlook Park starting 1 hour prior to your wave start. Note: Any swag/bibs not claimed by race start will be gifted to race-day volunteers.

3. Parking & Vehicle Camping

  • Runner Parking: Primary parking at Overlook Park is reserved for registered runners. Overflow parking is available along Pacific Ave and at the nearby staging area (staging area parking requires a paid fee—please obey posted local signs).

Course map

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