Articles

Belgian Ultrarunner Karel Sabbe's Record-Breaking Pacific Crest Trail Run Showcased in New YouTube Documentary

Explore Karel Sabbe's record-breaking Pacific Crest Trail run in a riveting documentary. Jour..

Trail Running: How it Can Help Reduce Stress and Anxiety

Trail running is an effective way to reduce stress, anxiety, and improve physical and mental he..

Trail Running vs. Road Running: Which One Is Right For You?

When it comes to running, there are two primary options to choose from: trail running and road..

Sean O'Brien 100K

Name: Sean O'Brien 100K
Start: 2027-01-23
End: 2027-01-23
Location: Calabasas

Calabasas, United States • 23 Jan 2027

Sean O'Brien 100K/50M/50K/26.2/30K - January 31, 2026

This event is a set of trail races held in Calabasas, CA, with a listed venue at 1925 Las Virgenes Road. The program for the date includes multiple distances on trail terrain and references course viewpoint photos such as Mile 7 and Mile 15 and general trail views.

The 100k distance is designated as a 2026 WS100 qualifier. The event appears as part of a trail race series and includes marathon and shorter ultramarathon options. The page for the event lists maps and directions for the location.

Distances offered include:

100k
50 mile
50k
Marathon (26.2)
30k

The description presents factual details about location, offered distances, and the qualifier status for the 100k. No start or finish times are provided in the available information. Visit the organization's website for the most recent information.

United States California Calabasas

Race information

Website Registration

100 km

100k

50 mi

50 Miler

50 km

50k

26 mi

Marathon

30 km

30k

Visit the organization's website for the most recent information.

Trail runs nearby

Saturday Apr 25

Virgenes Canyon Trail Races

...

Las Virgenes Canyon Ultra Trail Races on April 25, 2026 in Woodland Hills, CA offers distances from 6K to 100K on rugged trails with climbs and open views. Aid stations are fully supported, the event is cupless and there are food and awards..

Sunday Apr 26

Aut2Run For Autism

...

A multi-distance running event at CSU Channel Islands on April 26, 2026, with in-person and virtual options; 100% of proceeds benefit Autism Society Ventura County's local programs.

Sunday Apr 26

Northeast Trail 5K

Los Angeles

5 km

Support youth programs while running or walking through beautiful Griffith Park. This community trail event features a 5K course for all ages and offers medals and t-shirts to the first 500 participants.

Saturday May 2

Santa Clarita Trail Race

...

This trail race in Santa Clarita's historic Placerita Canyon offers a wide range of distances, from a 5K to a 120K ultramarathon. The course travels through the golden hills of the East Walker Ranch Open Space, featuring singletrack trails..