Colorado Multisport Calendar

  • Boulder Rez Marathon

    Boulder Reservoir 5275 Reservoir Road, Boulder, CO, United States

    This amazing run course will take you alongside the Boulder Reservoir, remaining mostly on dirt roads and trails. The course is flat with only 200 feet of gain, and will provide views of the Boulder Reservoir and Rocky Mountains. Marathon, 3/4 Marathon, Half Marathon, 10K, Relay

  • Boulder Sunset Triathlon

    Boulder Reservoir 5275 Reservoir Road, Boulder, CO, United States

    Join us for an unforgettable morning at the Boulder Reservoir. Although this race does not take place at sunset, it will take place at the end of the summer-- it's sister race is the Boulder Sunrise in June. Experience gorgeous views at the recently upgraded venue. All participants receive stellar race shirts and finisher medals, […]

  • Yeti Chase 5K & 10K

    Bear Creek Lake Park (Lakewood) 15600 W. Morrison Road, Lakewood, CO, United States

    The Yeti Chase 5K & 10K take place at beautiful Bear Creek Lake Park in Lakewood. This is the 13th year for the Yeti Chase, and it has sold out well before race day in all previous years. After chasing down the Yeti, runners wander the park's 2,500 acres, known for it's diverse bird and […]

  • Ralston Creek Half-Marathon & 5K

    Arvada Arvada, CO, United States

    The Ralston Creek Half-Marathon & 5K has become Colorado’s premier winter half marathon! Finisher Medals for Half Marathon finishers and a generous 4:30 cutoff time. Courses follow a scenic mix of road and bike path through Arvada's beautiful west side. Long-Sleeve Gender-Specific Tech Shirts, hot cocoa, breakfast burritos from El Senor Sol Mexican restaurant, and […]

  • NOCO Half Marathon & 10K

    Boyd Lake State Park (Loveland) 3720 N County Road 11-C, Loveland, CO, United States

    Spring is the season of renewal and running. We hope you join us for a fun adventure that embodies the spirit of springtime at the beautiful Boyd Lake State Park! Choose from the Half Marathon (13.1 mile) or 10K (6.2 mile) for your run adventure. This course is on smooth paved walkways with about three […]

  • Boulder Sunrise Triathlon

    Boulder Reservoir 5275 Reservoir Road, Boulder, CO, United States

    Kick off your summer of racing in Boulder.

  • Boulder Rez Marathon

    Boulder Reservoir 5275 Reservoir Road, Boulder, CO, United States

    This amazing run course will take you alongside the Boulder Reservoir, remaining mostly on dirt roads and trails. The course is flat with only 200 feet of gain, and will provide views of the Boulder Reservoir and Rocky Mountains.

  • Boulder Sunset Triathlon

    Boulder Reservoir 5275 Reservoir Road, Boulder, CO, United States

    Join us for an unforgettable morning at the Boulder Reservoir. Although this race does not take place at sunset, it will take place at the end of the summer-- it's sister race is the Boulder Sunrise in June. Experience gorgeous views at the recently upgraded venue. All participants receive stellar race shirts and finisher medals, […]

  • Yeti Chase 5K & 10K

    Bear Creek Lake Park (Lakewood) 15600 W. Morrison Road, Lakewood, CO, United States

    The Yeti Chase 5K & 10K take place at beautiful Bear Creek Lake Park in Lakewood. This is the 13th year for the Yeti Chase, and it has sold out well before race day in all previous years. After chasing down the Yeti, runners wander the park's 2,500 acres, known for it's diverse bird and […]

  • Ralston Creek Half-Marathon & 5K

    Arvada Arvada, CO, United States

    The Ralston Creek Half-Marathon & 5K has become Colorado’s premier winter half marathon! Finisher Medals for Half Marathon finishers and a generous 4:30 cutoff time. Courses follow a scenic mix of road and bike path through Arvada's beautiful west side. Long-Sleeve Gender-Specific Tech Shirts, hot cocoa, breakfast burritos from El Senor Sol Mexican restaurant, and […]

  • Three Creeks Half Marathon

    Bear Creek Lake Park (Lakewood) 15600 W. Morrison Road, Lakewood, CO, United States

    Racing Underground brings you an amazing half marathon this spring! The Three Creeks Half Marathon features a half marathon course that is flat, fast and scenic! Travel on foot through some of the most beautiful parts of Cherry Creek State Park, with a total combined elevation gain of only 291 feet spread out over 13.1 […]

  • Boulder Rez Half

    Boulder Reservoir 5275 Reservoir Road, Boulder, CO, United States

    This spring race features a spectator-friendly Half Marathon, 10K and 5K course. Attracting athletes from all over the west due to its phenomenal scenery, glamorous finisher medals, perfect running temperatures with many nearby Boulder attractions to enjoy after the race. The run course loops around the Boulder Reservoir and remains mostly on dirt trails. The […]

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