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

102.5-mile loop in Colorado's San Juan Mountains, 33,000 feet of climbing, 13 mountain passes, technical terrain, summit of Handies Peak at 14,048 feet

High-altitude 50-mile out-and-back over dirt, rocks, and mud with challenging climbs, fast descents, and views of Leadville’s historic mining district

Steep, technical 100-mile route through Colorado’s rugged San Juan Mountains, renowned for extreme difficulty and a strict no-frills ethos

101-mile loop in Colorado’s Sawatch Range with 23,500 feet of climbing, high alpine passes, ghost towns, and sweeping ridges on the Continental Divide

Alpine Loop course through historic mining ghost towns, reaching 12,930 feet at California Pass and descending to Silverton, total gain 4,400 feet

Scenic alpine 10K loop with 1,546 feet of vertical gain per lap, technical trails through aspen groves and meadows at Powderhorn Mountain

Challenging 50K ultra crossing all four Aspen Snowmass mountains on singletrack and dirt roads, featuring demanding elevation and scenic mountain terrain.

2km out-and-back laps on the Thumb Open Space trail, with 540 feet of climbing each lap and a sustained focus on vertical gain.

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

San Juan Mountains singletrack, Bachelor Loop, North Clear Creek Falls, two Continental Divide crossings, above 12,000 feet, historic mining scenery

50-mile route from Bear Creek Regional Park through High Drive, Cheyenne Canon, and notable landmarks including Seven Bridges and Helen Hunt Falls

Technical trails across the flat-topped Grand Mesa, high-altitude forests, alpine meadows, lakes, and streams

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.

200-mile point-to-point course from Fort Collins to Steamboat Springs with mountain passes, open spaces, and road sections

High-altitude courses over 10,600 feet, technical trails and remote forest service roads, striking mountain views, and challenging wilderness terrain

Aspen 50K route featuring demanding ascents, out-and-back to McNamara Hut, diverse terrain, and Elk Mountains scenery, starting at Rio Grande Park

High-alpine course over flowing singletrack and rugged mountain paths, finishing in town with mountain views and community atmosphere.

Unmarked 90–105 mile route through the San Juans, over 40,000 feet of climbing, five 14er summits, and self-chosen path between checkpoints