100K ultramarathons in California, United States

Northern Sierra Nevada trails with steep elevation gains, raw terrain, and views of mountain lakes, granite ridges, and dense forests

Scenic 2-mile loop at Harvey Bear Ranch with hill and mountain views, multiple distance options, generous cutoff times, and a community-focused environment.

Bay Ridge 100k and Firetrails 50-mile ultras commemorating Dick Collins, featuring P-USATF Grand Prix competition and UTMB points eligibility

Three-loop course through Cuyamaca Rancho State Park, summiting Cuyamaca Peak, circling Oakzanita Peak, and running PCT segments with desert views.

Mountain routes near Los Angeles featuring Big Bear Lake views, Sugarloaf Mountain ascents, and descents into Siberia Canyon

California Classic singletrack ultramarathon with Lake Sonoma views, generous cutoffs, strategic aid stations, and late season wine country scenery

Rugged Los Padres trails over the Gaviota Coast with steep climbs, panoramic ridgelines, ocean and island views, and up to 25,000 feet elevation gain

Rugged Santa Monica Mountains singletrack on the Backbone Trail, with ocean views and nearly 11,000 feet of climbing on the 50-mile course.

Rugged loop course through Goodan Ranch Sycamore Canyon Preserve, varied natural terrain and canyon views just east of San Diego.

Remote Tejon Ranch fire roads through canyons, creekside stretches, oak groves and sagebrush plains, with Grapevine switchbacks and expansive mountain views

Scenic, demanding mountain routes on Marin County trails, including a tough 50K loop and 100K point-to-point with sweeping Bay Area views.

Route featuring Pritchett Peak climb, rolling descents to Lake Sonoma, out-and-back on the original course, and scenic finish at Coyote Sonoma

50-mile trail ultra in Angeles National Forest near Lake Hughes, crossing the Leona Divide twice and spending time on the Pacific Crest Trail.

Rugged Sierra Nevada foothills, historic gold-rush routes, steep canyons, and challenging scenic terrain through the birthplace of mountain ultras

Challenging 10-mile trail loop with 1,400 feet of elevation gain per lap, lake views, runnable terrain, frequent aid stations, and camping available

62-mile course in the Marin Headlands, over 11,000 feet of elevation, single-track trails and dirt roads, views from redwoods to coastal cliffs

Winding trails through Placerita Canyon’s historic gold discovery site, challenging hills, and golden Southern California landscapes

Hilly single track and fire road routes through oak forests and meadows, with ridgeline views of Santa Clara Valley and Santa Cruz Mountains

High-altitude ultramarathons on exposed, rocky 4WD dirt roads and single-track trails in the Eastern Sierra foothills, with variable weather and minimal tree  

Full-moon trail weekend with evening starts, steep sustained climbs, high-elevation terrain to 6,200 feet, and rugged mountain-style efforts.