October ultramarathons in Arizona, United States

50- or 100-mile clockwise loop around Prescott, linking standout singletrack and backcountry trails across rugged central Arizona terrain

Unmarked 45-mile loop from Schultz Creek Trailhead, Flagstaff, with 3,300 feet elevation gain and minimal aid on evolving singletrack routes

Ancient canyon trails past petroglyphs, 1,200-foot climb to Spider Rock overlook, sandy stretches, creek crossings, and sweeping desert vistas

Looped 50-mile course through rugged Mingus Mountain with 7,300 feet of elevation change, rocky trails beneath tall pines, and shared with horses

Desert sand and slickrock routes past Antelope Canyon and Horseshoe Bend, with singletrack loops and Lake Powell views near Page

Steep, rocky paths and open sun exposure on the Maricopa Trail, finishing in Cave Creek Regional Park with wide Sonoran Desert views

Rolling singletrack loops on the scenic Pemberton Trail, desert views, and a festive atmosphere in McDowell Mountain Regional Park

Rugged, remote Woodchute trails on Mingus Mountain; 6,000 feet of gain over 32 miles; tough terrain better suited for hiking than running