FOURmidable

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.

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).