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Sean O'Brien 100K

Name: Sean O'Brien 100K
Start: 2027-01-30
End: 2027-01-30
Location: Calabasas

Calabasas, United States • 30 Jan 2027

Sean O'Brien 100K/50M/50K/26.2/30K : Calabasas, CA

The event takes place Saturday, January 30, 2027, at 1925 Las Virgenes Road in Calabasas, California. It is organized as a series of trail running distances on local trails.

Distances offered include:

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

The 100K is designated as a 2026 Western States 100 (WS100) qualifier. Registration for the event opens Wednesday, July 1, 2026 at 6:00 AM Pacific Time. The event listing identifies multiple viewing locations along the course and references trail views and specific mile markers.

Information presented focuses on the race options, qualifier status for the 100K, and the event location. No start time or course technical details 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

26.2

30 km

30k

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

Trail runs nearby

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Malibu Canyon Trail Races

...

Trail races at Point Mugu State Park in Malibu on June 6, 2026, offering distances from a half marathon to a 100K; the event is sold out with a waitlist and volunteers can trade shifts for a free entry.

Sunday Jun 7

Griffith Park Trail Marathon Relay & 8K

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5 mi

26 mi

Experience a scenic trail race through the iconic landmarks of Griffith Park in Los Angeles. Choose between a five person marathon relay or an individual 8K loop featuring live music and full course support.

Saturday Jun 13

ABWR Half Marathon - Glendale

Phoenix Rising is a multi distance trail race in Griffith Park Los Angeles offering 5k, 10k, 15k and a half marathon on marked out and back and loop courses. The event includes aid stations, finisher medals and free photos.

Sunday Jun 14

Old Zoo Half Marathon

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12 km

13 mi

A second annual running event at the Old Los Angeles Zoo area on June 14, 2026, offering a half marathon and a 12K on relatively flat, scenic trails. Registration runs November 21, 2025 to January 26, 2026 with fees from $49.