Welcome to the home of Colorado's Largest Trail Race Series. The Endurance Race Series presented by Asics is made up of nine different trail race events.  Whether a competitive racer, an avid runner, or a trail beginner our trail races have what you need... challenging yet beginner friendly race courses, great mountain views, a family friendly atmosphere, and post race festivals that keep the event party going all morning long!! 

We offer a Half Marathon and 10k option at ALL 9 of our races, and a 5K option at at 4 of those 9. NEW in 2014... the Kids Half Mile Dash powered by the Western Dairy Association. 

2014 Registration is now available for ALL races. Registration can be found on:



April 20th, 2014- Westminster Trail Marathon, 10k, 5k
 April 26th , 2014-Ft. Collins Trail Half Marathon and 10K (NEW EVENT)
July 12-13, 2014- Colorado Running Festival at Copper Mountain (NEW DATE)
July 19th, 2014- Keystone Half Marathon, 10k, 5k
August 10th, 2014 - Beaver Creek Half Marathon and 10K
August 16th, 2014 - Glenwood Springs Half Marathon and 10K
September 7th, 2014 - Denver Trail Half Marathon and 10K
September 28th, 2014 - Snow Mtn Ranch Half Marathon, 10k, 5k
October 12th, 2014 - Louisville Trail Half Marathon and 10k

 ONSITE EVENT DISCOUNTS: visit us at one of these upcoming races, and sign up for one of the 2014 ERS events and get ANY of of Half Marathon for only $50, or 10k's for only $25.  (offer valid onsite only) 

        • April 13, 2014 Horsetooth Half Marathon (Ft. Collins)


Register Now- Season Pass!!