RMRR provides consistent and individualized marathon training opportunities for runners of all abilities.
All races in the series are low cost, friendly, fully supported, and officially timed.The first two races, March 29 & April 11, are 10 Mile and 20 Mile races (runners choice for distance). The third race in the series is the Inaugural Blue Heron half marathon. All you need to do is focus on your running! Our races fit perfectly in training schedules for Boston, London, Colfax, and other spring full and half marathons.
Everyone is welcome to Marathon Training Series races: RMRR members, guests, training team members, everyone! The course is clearly marked, and mile markers will help you gauge your time. Aid stations will have water, sports drink, and gels. Winners of each distance will receive ribbons and running store gift certificates. We make it easy for you to work on your pace, your nutrition and drinking, and getting everything ready for your big race.
RMRR members get a 50% discount (automatically taken at registration check out). Race day registration will be available.
Please note that for everyone's safety dogs or running strollers are not permitted on our courses. Thanks for understanding.
The races begin at 8 am at the Platte River Trailhead Park in Thornton, at 88th and Colorado.
Apr 11, 2026
Distance — 10 Miles
Type — Running
08:00
$20.00
Apr 11, 2026
Distance — 20 Miles
Type — Running
08:00
$30.00
These values represent the 3-year monthly averages for April in Thornton.
Thornton is a city of about 144,000 in the Denver Metropolitan Area of the western U.S. state of Colorado. The city lies northwest of Denver in Adams and Weld counties. It is a diverse community with a strong commitment to quality of life and environmental issues.
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location_on Thornton, Colorado, US
calendar_today Mar 29, 2026
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