Sean O'Brien 100K

The Anytime Runners 12H Training Run is a supported endurance event held at Griffith Park, Los Angeles, specifically at the Crystal Spring Picnic Area. Participants run or walk on a mostly flat 3-mile loop trail for up to 12 hours, from 6 AM to 6 PM, with the flexibility to start anytime between 6 A..

Tough Mugu is a challenging trail running event held at La Jolla Group Campground in Point Mugu State Park, Malibu, California. Featuring two distances, a 25k and a 10k, the race offers runners stunning coastal mountain views, including the famous Ray Miller Trail, Channel Islands, and Boney Mountai..

The SoCal Summer 6K/12K, hosted by Pasadena Running Company, is a trail running event held at Lower Arroyo Park in Pasadena, California. Scheduled for a summer Friday evening, it offers two distance options: a 6K (3.9 miles) and a 12K (7.8 miles, two loops of the 6K course). The course features mixe..

The Bulldog Ultra is Southern California's oldest 50k trail race, held in the scenic Santa Monica Mountains at Malibu Creek State Park in Calabasas, CA. Celebrating over 30 years, it offers two challenging distances: a 25k trail run and a 50k ultra, featuring steep climbs and rugged terrain with ove..

No Name 5025 is a trail running event held at Cheeseboro National Park in Woodland Hills, California. It features a challenging 50k ultramarathon, along with a half-marathon, 5k, and a kids’ 2k fun run. The course offers diverse terrain, including runnable ascents, winding singletracks, steep fire r..

The Cheeseboro Canyon Trail Run, held in Agoura, California within Cheeseboro National Park, offers a variety of trail running distances including a challenging 50K ultra marathon, a half marathon, a 5K trail run, and a new kids 2K fun run. The courses feature diverse terrain with runnable ascents,..