O'brien Trail Races
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Event Details
The O'Brien Trail Races take place at William O'Brien State Park in Marine on St Croix, Minnesota. The races start at the park's Visitor Center.
Distances
The event offers four trail running distances:
- 50K
- 25K
- 10K
- 5K
Course Information
The 50K consists of two 25K loops using the upper and south sections of the park and Jackson Meadows. The 5K and 10K courses use wide grass trails. The 10K route involves running the 5K course twice. There is one large hill on the 5K/10K route, with a flat finish.
Registration and Fees
Online registration opens on November 28, 2025, and closes on September 21, 2026. Race day registration is available at a higher fee. Entry fees vary by distance and registration date. For the 5K and 10K, the fees are $5 and $10 respectively, even on race day. Race shirts are an optional addition to the entry fee.
Aid and Amenities
For the 50K and 25K, there are four aid stations per loop. Aid stations typically offer water, Gatorade, cookies, and other items. Post-race food includes bottled water, soda, cookies, chips, and pickles. Bathrooms are available inside the Visitor Center at the start/finish area. Packet pickup is on race morning only.
Policies
There are no refunds, and entries cannot be transferred, deferred, or applied to another event. If the event is shut down, it will become a virtual race. Visit the organization's website for the most recent information.
