American Trail Running Association

The American Trail Running Association, ATRA, was formed in mid-1996 as a Colorado not for profit corporation to serve the trail and mountain running community. Our mission is to represent and promote trail and mountain running. We offer individual, club, race and corporate memberships.

Boulder Trail Runners

We are people who enjoy running the trails near Boulder, Colorado. Happy Hour Run is EVERY Thursday at 5:30 pm: all year, all weather, all trails. You should go to this; it's best way to meet people and see what's up. The location changes every week and is announced on this List. Show up!