Event details subject to change. Please confirm all information via event website.

  • Pioneer Prairie Dog Half Marathon

    Prairie Dog Race Series
    Westminster Promenade 10600 Westminster Blvd, Westminster, CO, United States

    Welcome to the Pioneer Prairie Dog Half Marathon event; the one that started the series! With 10k and 5k events too! Everyone is back to school and slipping into a routine. Make this your mental health break as you break away from the chaos of weekly schedules and give yourself a morning to race in […]

  • Eltuck Valley 12K

    Lory Summer Trail Series
    Lory State Park 708 Lodgepole Dr, Bellvue, CO, United States

    Join us each Tuesday evening in August for a fun series of shorter midweek trail races. Our goal is to offer a fun, low-key series of races designed to give newer trail runners an opportunity to dip their toes into the trail racing waters, and to offer more experienced trail racers a chance to sharpen […]

    $25
  • Rock Hawk Trail Race

    Phillip S. Miller Park 1375 West Plum Creek Pkwy, Castle Rock, CO, United States

    Held on the gorgeous, thrilling and rolling trails of Castle Rock’s Miller Park & Ridgeline Trail systems. While not overly technical, these trails will challenge and excite, as you soak up the amazing views. This is an excellent race for both first-time and veteran trail runners, and provides a nice test for those who are […]

  • Boulder Sunset Triathlon

    Boulder Reservoir 5565 N 51st St, Boulder, CO, United States

    Summer may be coming to an end, but our tri season is still heating up! Join us at the Boulder Reservoir for the 13th Annual Boulder Sunset Triathlon, a local favorite. For the 5th year in a row we are the proud host of the Mountain Collegiate Conference race and the USAT Duathlon Race Series. […]

  • RexRun 5K for PAWSitivity

    Arapahoe County Fairgrouds 25690 E Quincy Ave, Aurora, CO, United States

    The RexRun 5K is a 5K run/walk to spread mental health awareness and #PAWSitivity in schools with the help of more Therapy K-9's like Arapahoe County Sheriff's Office K-9 Rex. This year's event is at Dove Valley Park in Centennial on August 6th.

    $30 – $60
  • Boulder Sunset 5K/10K

    Boulder Reservoir 5565 N 51st St, Boulder, CO, United States

    The Boulder Sunset 10K & 5K Run is part of BBSC’s biggest endurance event of the summer. Spend your weekend racing with BBSC at the incredible and scenic Boulder Reservoir. Register, and start training for the end-of-the-summer endurance festival with BBSC.

  • Thirsty 13 Half Marahton

    Ska Brewing Durango, CO, United States

    It's a race.  It's a Brewfest.  It's the Thirsty 13 Half Marathon! Are you thirsty for gorgeous scenery?  You won't find a course more beautiful than this one.  With the majestic La Plata mountains in the background, you'll cruise through the lush pastures of Wildcat Canyon and past the pristine waters of Lake Nighthorse.  This […]

  • RMRR Fall Marathon Training Series

    Riverwalk Ballfields 9830 Riverdale Rd, Thornton, CO, United States

    RMRR’s Marathon Training Series provides 10M and 20M races that are low cost, friendly, fully supported, and officially timed.  All you need to do is focus on your running!  Our races fit perfectly in training schedules for Colfax, Boston, New York, Chicago, and other full and half marathons. Everyone is welcome at our MTS races:  RMRR members, […]

  • Bluffs 8K Trail Run

    South Suburban Race Series
    Prairie Sky Park 10249 Ridgegate Circle, Lone Tree, CO, United States

    The Bluffs 8K Trail Race has rolling hills and beautiful views as you run or walk through the Bluffs Regional Park. The race will start/finish near the Prairie Sky parking lot o n August 28th.

  • Grand Traverse Mountain Run

    Mt. Crested Butte Mt. Crested Butte Ski Resort, Crested Butte, CO, United States

    The Grand Traverse Mountain Run is a point-to-point ultra marathon from Crested Butte to Aspen, Colorado. The course follows the route of the Grand Traverse Backcountry Ski race. In total, runners travel 40 miles across the Elk Mountains with over 6,000′ of elevation gain.

  • Please click here to submit your event for FREE to our online calendar.
    We do not allow events without physical locations (IE – virtual runs, runs with locations TBD, etc…).
    Please allow 48 hours after submission for an event to appear on the calendar. If you have already listed your event and would like us to update it, please contact us.