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Sean O'Brien 100K

Calabasas, United States • 31 Jan 2026

Event overview

The Sean O'Brien trail races take place on Saturday, January 31, 2026, in Calabasas, CA. The event is based at 1925 Las Virgenes Road. Multiple trail race distances are offered on the same day. The 100K distance is a 2026 Western States 100 (WS100) qualifier.

Race details

Distances offered:

  • 100K
  • 50 Miler
  • 50K
  • Marathon (26.2)
  • 30K

Registration closes Friday, January 2 at 11:59 PM PT. The event listing includes course view references such as Mile 7 and Mile 15 views. 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
26.2
30 km
30k
Visit the organization's website for the most recent information.
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