Fourmidable

FEB
20
2027
Experience a trail running event in Auburn featuring four major climbs and 6000 feet of elevation. Choose from distances ranging from 13km to 50km on a course with less than one mile of pavement.
Sat 20 Feb 2027
50 kilometers 35 kilometers 13 miles 13 kilometers

Always double-check with the organizer's website! This page may contain affiliate links.

FOURmidable Trail Races

The FOURmidable event takes place in Auburn, California, with all race distances starting and finishing at Overlook Park. The routes predominantly utilize trails, with less than one mile of road running across all distances. The available race distances include:

  • 50 km
  • 35 km
  • Half Marathon (21.1 km)
  • 13 km

The 50 km course features an accumulative elevation gain of over 6,000 feet. The route incorporates four primary climbs: Cardiac Hill, K2 (also known as Training Hill), Knickerbocker at the Old Auburn Dam Site, and Overlook Hill.

This is a cupless event, meaning participants are responsible for bringing their own reusable cups or water bottles for hydration. Aid stations along the course are staffed by volunteers and provide supplies such as soda, boiled potatoes, candy, gels, electrolyte drinks, and salt tablets.

Available amenities include early packet pickup the day before the race at Overlook Park. On the day of the event, packet pickup is available starting one hour before each race start. Participants may camp in vehicles or trailers at the start area on the Friday night before the event, though ground tents and campfires are prohibited. Parking at the main venue is reserved for registered runners, with additional paid parking located nearby. All finishers receive custom race swag and a post-race meal. Visit the organization's website for the most recent information.

50 km
50k
35 km
35k
13 mi
Half Marathon
13 km
13k

Events nearby

A trail 5K and 10K at Granite Beach for runners with or without dogs, featuring shaded single-track trails, mid-course aid stations, finisher medals and dog bandanas.
Trail races at Mammoth Bar OHV Area in Auburn State Recreation Area on September 6, 2026. Options include a 13.1 mile half marathon and a 6.2 mile 10K, each with notable elevation gain and staffed aid stations.
Mile Madness is a looped trail endurance event in Auburn, California, held September 18-21, 2026. Timed events run from 3 to 72 hours with a 0.75 mile loop and options including a 100 mile race plus on-site aid and amenities.
Trail runs at Granite Beach on Folsom Lake with new 10 mile and 5K courses, aid stations, age group awards, a finisher beer glass and a postrace meal.
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