Intermediate 100K ultramarathons in Colorado, United States

High-altitude trails above 10,000 feet through alpine meadows, ghost towns, and mining relics, with sweeping views of the South Park Valley and Decalibron peaks

Rugged high-altitude ultramarathon through State Forest State Park, with alpine lakes, rocky ridges, remote trails, and 14,500 feet of elevation change

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

Diverse and challenging dirt and single-track trails, panoramic vistas, moderate elevation gain of 1,930 ft (50km) and 4,250 ft (100km)

Flowing singletrack, mesa climbs, red slickrock cliffs and buttes, with overlooks above the Colorado River and wide-open desert views.

Smooth single and double-track routes through Mueller State Park, spring-fed meadows, Pike Peak granite formations, and sweeping Colorado mountain views

Mountain trail course through Colorado Springs, featuring climbs, descents, scenic parks, and iconic landmarks. Start and finish at Rock Ledge Ranch.