December ultramarathons in California, United States

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

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.

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

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

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

Scenic and challenging trails in Orange County’s Chino Hills open-space park

Rugged dirt and rocky single-track trails through rolling hills, frequent ascents and descents, sweeping lake views, and minimal pavement at Cronan Ranch

Rolling hills and tree-covered trails through a 2,700-acre former Paramount Pictures expanse, with vibrant scenery and rugged terrain

Twisting singletrack through redwood groves, shaded canyons and ridge-top chaparral, with plenty of climbing and expansive Peninsula views.

Repeated climbs of Cardiac Hill on a 2.5-mile out-and-back loop over challenging terrain in a 6-hour trail event

USATF-certified 1.0-mile loop around Cottonwood Lake with lake views, challenging endurance events including 24 Hour Solo and 100 Mile distances