Cirque Series - Arapahoe Basin
Keystone, United States • 5 Sep 2026
Event overview
Cirque Series at Arapahoe Basin takes place on September 5, 2026 in Keystone, Colorado. The race distance is 9.4 miles with 2,211 ft of elevation gain. The field is capped at 700 runners. A National Forest fee of $2.00 applies. Early bib pickup is available Friday, September 4, 2026 at La Sportiva retail store, 2100 Broadway, Boulder, CO. The course is on established trails in the White River National Forest.
Course
The route begins at 10,780 ft at Mountain Goat Plaza and climbs via High Noon parking, Last Chance, and the A-Basin summer road to Black Mountain Lodge. The course includes a new uphill section toward Zuma Cornice, crosses to the top of Montezuma Lift, and follows the Lenawee trail to Little Lenawee summit, then returns downhill. Downhill sections include the Half Moon Vista singletrack and the Argentine North Fork singletrack, finishing back in Mountain Goat Plaza. The finish area will feature live music and food.
Categories, cutoff and services
Three entry categories are offered: Sport, Expert, and Pro. Registration splits are listed as 67% Sport, 28% Expert, and 5% Pro. The course is subject to a strict cutoff at Black Mountain Lodge Aid Station #1 (35 minutes). Hydration is provided at two on-course aid stations and the finish line. The race uses disposable timing chips on the back of bibs.
Safety and rules
The organizer notes steep and technical sections, especially near Little Lenawee summit. The course will be marked with flagging. Competitors are asked to follow flagging precisely, use careful footwork in technical areas, and follow the rock-warning procedure described on course. Rules include leave-no-trace, no littering, and no trespassing on private property. Prizes and season points are awarded by category, with cash prizes for Pro places and gear awards for Expert and Sport places. Visit the organization's website for the most recent information.