New Castle’s Downvalley Dirty Dozen MTB

New Castle Trails’ 2026 Downvalley Dirty Dozen is a reimagining and celebration of trail running, mountain biking, music, and community. The weekend is full of fun, including live music from regional bluegrass bands, plus mountain biking and trail running races for all ability levels on the Colorow and Highlands trail networks. Racers can also enter the duathlon option to run and bike! Cash and gear prizes will be awarded for each race. See the website link for registration, course maps, race results, and race details.

The Dirty Dozen MTB Race includes a fun and challenging MTB race with a neutral rollout on the Colorow and Highlands Trail Networks Saturday, 8/1 · 7:00 am start from Alder Park · ~3,800 ft of climbing on singletrack · $95

The Dirty Half Dozen MTB Race is a shorter course (7 miles) for those not quite ready for the full Dozen race course and is perfect for Middle and High School Racers. Saturday 8/1 · 9:30 am start from Alder Park · ~1,000 ft of climbing on singletrack · $75
Post-race awards and party at 3:00 pm at Down Valley Brewing on Main Street.

If competing in one race just isn’t enough for you, register for both the MTB Race (20-mile course) and the 10K Trail Running Race, and you’ll get your own combined category. Awards for the Run and Combined categories will be held after the races on Sunday.