December ultramarathons in United States (Southwest)

Scenic Lake Ray Roberts routes with well-groomed single-track and technical segments featuring roots, rocks, and varied North Texas terrain

Classic Northern California terrain: flowing singletrack, rolling dirt paths, stout climbs, heat, exposure, and wide-open vistas.

Scenic desert landscapes, rolling singletrack, quick ascents and descents on a mix of classic and newer trails in McDowell Mountain Regional Park

Coastal trails through Point Mugu State Park, panoramic ocean views, rugged climbs, and rejuvenated landscapes with blooming flora

Loop through rolling Spangler Hills desert terrain on jeep roads, singletrack and sandy washes, with expansive views of the Southern Sierra.

High desert ultramarathon on the Arizona Trail with out-and-back segments, expansive views, and northern ridgeline passages near the Santa Rita Mountains

Classic hill country single track, rocky sections, open fields, creek beds, cacti, bluffs, and ravines along the San Gabriel River near Austin

High-altitude 50k on technical trails through Staunton State Park, featuring rugged mountain terrain, granite cliffs, meadows, and frequent wintry conditions.

Flat, fast, multi-loop trail on hard crushed rock and soft paths amidst Brazos Bend State Park wildlife, with frequent aid stations and ideal December weather

Point-to-point 50-mile course from Sunrise Trailhead through Cuyamaca Rancho State Park, forested trails, and Oriflamme Canyon to the desert floor finish.

1km out-and-back trail with a 540-foot ascent, poker chip turnarounds, and milestone awards for multiple ascents

Last-man-standing format on a challenging 4.5-mile trail loop near the Texas-Oklahoma border, designed for higher difficulty and originality

Scenic 10k desert loop near St. George with alternating directions, varied distances, and supportive trail running atmosphere

Certified paved loop on the shore of Lake Grapevine, with lake views, changing direction, and a spectator-friendly timed ultra format.

Millerton Lake and San Joaquin River trails with scenic valley views, 50k route, regular aid stations, and crew access at River Gorge Management Area

No-frills urban ultramarathon from Twin Peaks with 50K or 50-mile routes through city landmarks, limited aid, and self-navigation challenges

6-mile loop course from Confluence Park with 1.5-hour cutoff per loop, up to 17 loops for 102 miles, progressive elimination format

Scenic 50K and Half Marathon with generous cutoffs, trekker-friendly course, and capped field for an intimate year-end event