Hardest ultramarathons in United States (Southwest)

Looped mountain course in Summit County with single track trails, forest roads, and recreation paths, over 40,000 feet of elevation gain above 9,000 feet.

420-mile route from Salt Lake City to West Yellowstone, mostly paved roads with 50 miles of dirt, expansive terrain and multi-day endurance challenge

Rolling terrain on the Rainbow Trail beneath the jagged peaks of the Sangre de Cristo mountains, along the Southern Colorado Rockies wilderness boundary.

240 miles across expansive deserts, dramatic canyons, rugged slick rock, and two mountain ranges through Canyonlands and Arches National Park

Rugged loops around Lake Perris with 2,300 to 4,500 feet of elevation gain, lake and mountain views, frequent aid stations, and camping on site

304-mile point-to-point route through Sonoran Desert wilderness, remote backcountry trails, high-elevation mountains, and diverse arid landscapes

Single-loop Tahoe Rim Trail route around Lake Tahoe, with relentless climbing, constant elevation change, ridge lines, forest, meadows, and alpine lakes