Sean O'Brien 100K

The Sean O'Brien 100K is a trail running event held in Calabasas, California, offering multiple race distances including 100K, 50 miles, 50K, marathon, and 30K. The 100K race serves as a qualifier for the Western States 100. The course features scenic trail views with notable vantage points around miles 7 and 15, providing runners with beautiful natural surroundings.

This event attracts trail runners seeking challenging terrain and a competitive atmosphere. It is part of a series of trail runs organized by KHRaces, emphasizing endurance and outdoor adventure in the Southern California region. Visit the organization's website for the most recent information.