May ultramarathons in Colorado, United States

Fast, runnable 50K on soft dirt trail, with smooth cruising, open landscapes, and Pikes Peak views in southern Douglas County.

Single-track and jeep trails near the Arkansas River, historic Midland Railroad, challenging 50-mile course with over 7,000 feet of elevation change

Urban point-to-point 50K through Denver, linking five Denver Beer Co. taprooms from Olde Town Arvada to Littleton via Platte Street, Lowry, and South Downing.

Rugged double-loop course on scenic singletrack and dirt roads in Lory and Horsetooth Mountain Parks, over 11,000 feet of elevation gain and panoramic ridgeline

Cheyenne Mountain State Park 50k with crushed limestone, meadow and singletrack, climbing to Cheyenne Mountain before rocky pine-forest trails

Mountain trails near Rampart Reservoir with views of Pikes Peak; 60K point-to-point and vert-heavy 50K out-and-back with significant elevation

Gentle 4.167-mile out-and-back loop with 140 feet of gain, featuring asphalt track, smooth dirt roads, and wide riverside gravel paths

Timed ultra in Mueller State Park with a draw-by-chance loop format and all-dirt double-track and single-track trails.

Challenging loop with 1,200 feet of climbing per lap, fast singletrack, and summit views at Bible Point in elk country.

Loop and out-and-back course on 100% trails in Buffalo Creek Recreation Area, 6,700–8,400 ft elevation, 7,500 ft climb, pine forests and burn areas

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