Riverdale Ballfields in Thornton, Thornton CO
Sunday, September 21st, 2025
RMRRs Marathon Training Series (MTS) races are low cost, friendly, supported, accurately measured, well marked, and timed. Each MTS has 10mi & 20mi, or 20k & 30k options. All you need to do is focus on your running!
The MTS fits well into training schedules for Colorado Springs, Boulderthon, Long View, Chicago, Monumental (Indy), New York, and other fall full and half marathons.
Please note that for everyone's safety, dogs or running strollers are not permitted on our courses. Thanks for understanding.
RMRR Members receive a $5 discount off individual races and $15 off the 3-race bundles. Discount taken when you check out. Your membership must be current.
For more details and to register, please visit: RMRR Fall Marathon Training Series.
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