O'brien Trail Races
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O'Brien Trail Races : William O'Brien State Park, Marine on Saint Croix
The O'Brien Trail Races take place on September 26, 2026 at William O'Brien State Park in Marine on Saint Croix, Minnesota. The event is organized by True North Adventures and offers multiple trail distances on park trails and nearby Jackson Meadows. Races start and finish at the park Visitor Center; parking is in the Visitor Center lot.
- 50K: two 25K loops using the upper section, south section and Jackson Meadows
- 25K: single 25K loop, course details to be determined
- 10K: two laps of the 5K course on wide grass trails with one large hill
- 5K: wide grass trails with one large hill and a flat finish
The 50K uses two 25K loops, with four aid stations per loop, drop bags at the start/finish area, and awards for the top three male and female finishers. The 50K has a nine hour overall cutoff and requires runners to begin the second loop within four hours of the start. The 25K has four aid stations, a five hour cutoff, and awards for the top three male and female. The 10K and 5K have no aid stations, no awards, and no race shirts; all finishers receive a full color 8.5 x 11 print of the current year logo.
Packet pickup is race morning only. Bathrooms are available inside the Visitor Center. Participants should not use external music during the races unless using headphones. Post race food and aid station items are listed by the organizer. There are no refunds, and entries may not be transferred or deferred. If the event is converted to a virtual format, race shirts and numbers will be mailed within one week of the event's completion. Visit the organization's website for the most recent information.
