Weaving and rambling across the various rolling and steep hills of Jefferson County’s White Ranch Park, the Sawmill Trail Runs serve as an ultimate test for December running. Runners will enjoy a single loop for 27k, or the double for 55k. The route uses nearly all of the trails in White Ranch Park and boasts a challenging 4,229′ of elevation gain per loop.

The Sawmill Trail Runs quickly became an iconic HPRS Fat Ass starting in the winter of 2013. After 4 incredibly successful and adversity filled years, we decided to turn the event into an official race. It’s too good not to be a winter ultra offering in Colorado. While turning the event from Fat Ass to Official Race, we wanted to reward participants with a race with a “Fat Ass feel,” all while allowing them to gain points towards the Fat Ass Series (for members) and our Adversity Cup (everyone).  

Upcoming Races

Dec 11 2021
50 KM
8,458 8,458 ft.
Out and Back Course
10 :00 Cutoff
4 Elevation Rating
Very hilly, ~7500-12,500 feet in 50 miles
3 Surface Rating
Some rocks, root, and/or ruts


Date Finishers Top Result (M) Top Result (F)
12/12/20 17 3:41:00 4:32:00
12/14/19 41 5:23:00 7:31:00
12/08/18 56 5:41:00 6:01:00
12/09/17 29 4:56:00 6:59:00
12/10/16 No Finishers
12/12/15 No Results Posted. Submit Results
12/13/14 No Results Posted. Submit Results
12/14/13 No Finishers
We try to keep the most accurate information about this race, but changes do happen. Always visit the official race website for the most up to date information. If you see an error, please let us know

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