The Under the Shadow of the Peaks Endurance Double returns to Flagstaff, Arizona on September 19th through October 3rd, challenging runners with two signature Northern Arizona events in one season. This endurance challenge requires participants to complete either the Flagstaff to Grand Canyon Stagecoach Line 100-Mile Solo Run or the 55K Solo Run and then return for the full 26.2-mile Flagstaff Marathon on October 3rd, earning a special Endurance Double award upon completion.
The course begins at the Fort Valley Trailhead in Flagstaff's Coconino National Forest, setting runners beneath the San Francisco Peaks amidst historic Arizona Trail terrain. On race morning, participants navigate through pine forest and open meadows under clear blue skies or light clouds typical of late summer mornings in Northern Arizona’s high country. The atmosphere is one of quiet determination mixed with awe at the natural beauty surrounding them.
The Under the Shadow of the Peaks Endurance Double has been a tradition for several years now, bringing together endurance runners from across the United States and beyond who are drawn to Flagstaff's unique trails and challenging terrain. By participating in both events, athletes contribute to a community that values resilience and achievement at altitude, making it not just about running but also about camaraderie among like-minded individuals.
The Under the Shadow of the Peaks Endurance Double features two distinct courses: the 100-mile solo run from Flagstaff to Grand Canyon Stagecoach Line and the 55K Solo Run on September 20th. Both routes wind through pine forest, open meadows, volcanic terrain, and rolling singletrack, with elevations ranging between roughly 7,000 to nearly 9,000 feet for the longer event, offering a shorter yet equally demanding route for the 55K solo run. The Flagstaff Marathon course takes runners through Arizona Nordic Village trails within Coconino National Forest, providing miles of forest roads and singletrack at elevations above 8,000 feet.
Weather conditions are expected to be mild with daytime temperatures ranging between an average low of around 17°C (62°F) in the morning cooling off to a high of approximately 23.8°C (75°F). Precipitation is minimal, with no risk of rain during race hours and trail conditions remaining firm but slightly soft underfoot for steady footing.
The Under the Shadow of the Peaks Endurance Double offers endurance runners two signature Northern Arizona trail events: both the Flagstaff to Grand Canyon Stagecoach Line 100-Mile Solo Run or the 55K run, followed by a return visit on October 3rd for the full 26.2-mile Flagstaff Marathon.
Registration is required and can be completed online at [https://ultrasignup.com/register.aspx?did=139490](https://ultrasignup.com/register.aspx?did=139490) with no entry fee for either event, though participants must register separately for each. Bib pickup details are available on the website and typically occur at specific locations in Flagstaff a few days before race day.
The start location is the Fort Valley Trailhead in Coconino National Forest near downtown Flagstaff. Participants should be prepared to show proof of registration upon arrival and ensure they have adequate hydration, nutrition, and gear for running trails above 8,000 feet elevation over multiple hours or even several days depending on their chosen event.
The Under the Shadow of the Peaks Endurance Double concludes its endurance challenge in Flagstaff, Arizona, where runners complete two iconic Northern Arizona trail events. This multi-week test showcases not only physical endurance but also mental fortitude and community spirit among participants who tackle challenging terrain for a rewarding experience that celebrates both individual achievement and collective camaraderie.
