Eagle, CO. Come celebrate fall in the mountains with a trail running challenge! An exciting day of festival fun and adventure on the trails near Eagle, Colorado. With the start/finish line right in the heart of Eagle’s new fall festival, Septemberfest, friends and family can enjoy themselves while you push yourself in the rugged mountain race. Afterwards, relax with a beer, hot meal, or just sit and listen to live music. Racers can choose from a Half Marathon, Marathon or 50K.