100mi Spring ultramarathons in United States (West)

Rugged Wyoming wilderness, snow-covered trails, subfreezing temperatures, ski, bike, or run routes inspired by historic cattle drives

Flat, scenic dirt trail loop at Eagle Island State Park near Boise, Idaho

Badger Mountain Preserve trails with wide-open terrain and sweeping Columbia Basin views in Richland.

Scenic lap course through Reedley farmland, orchards, vineyards, and along the Kings River, racing from sunset through moonlit night to dawn

Double out-and-back course across asphalt, gravel, and dirt trails with over 10,000 feet of gain through Oregon parkland and small-town landscapes

105-mile point-to-point on remote singletrack through southern Arizona, with 12,500+ ft of climbing across desert, oak woodlands, and mountain terrain.

Remote Alaska winter ultra amid jagged limestone peaks, with steep climbs, glare ice, drifting snow, and constantly changing trail conditions.

Southern Utah desert course with mesa ascents, panoramic views, and technical terrain near Zion National Park

Ultra-distance courses along the Poudre River Trail from Watson Lake to Greeley, featuring scenic Northern Colorado landscapes and aid stations.

Looped course at Cesar Chavez Academy in south Corona foothills, with options for 1/4 or 1-mile loops and scenic day and night views

50-mile trail ultra in Angeles National Forest near Lake Hughes, crossing the Leona Divide twice and spending time on the Pacific Crest Trail.

Rugged Sierra Nevada foothills, historic gold-rush routes, steep canyons, and challenging scenic terrain through the birthplace of mountain ultras

Hard-packed salt and mud flats to the Islands, with rolling terrain and significant climbs on the longer courses.

Demanding mountain loop featuring 15,400 feet of elevation change, technical single track, and arid conditions through Cuyamaca and Anza Borrego State Parks

Fast 20-mile dirt loops on singletrack and double track, with rolling hills, 2,300 ft of climbing per loop, and a mild coastal spring setting.

Full-moon trail weekend with evening starts, steep sustained climbs, high-elevation terrain to 6,200 feet, and rugged mountain-style efforts.

Flat 1-mile dirt and grass loops on a private horse ranch in Riverside, lap-based ultra with accessible support and camping options for families and crews

Singletrack loop course at 7,200 ft in New Mexico's national forest, technical sections, elevation changes, solar-lit night running, free camping, no mid-race 


Rolling loop course at Lake Youngs Watershed with 900 feet of elevation gain per lap and a well-supported, community atmosphere

Distance options including 50 miles, 100k, and 100 miles in Northern Colorado, with team and solo entries, camping, and community atmosphere