Riverdale Ballfields in Thornton, Thornton CO
Sunday, August 23rd, 2026
RMRR provides full and half marathon training opportunities for runners of all abilities.
RMRR’s Marathon Training Series provides 10mi/20km and 20mi/30km races that are low cost, friendly, supported, and officially timed. All you need to do is focus on your running! The MTS fits well into training schedules for:
Everyone is welcome to Marathon Training Series races: RMRR members, guests, training team members, everyone!
Please note that for everyone's safety, dogs or running strollers are not permitted on our courses. Thanks for understanding.
The races begin at 7 am at Riverdale Ballfields at 9830 Riverdale Road in Thornton, Colorado.
RMRR Members receive a 25% discount, taken when you check out. Your membership must be current.
For more details and to register, visit the RMRR Fall Marathon Training Series page.