Rmrr Fall Marathon Training Series
About this race
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 Colorado Springs, Boulderthon, Long View, Berlin, Chicago, Monumental (Indy), New York, and other fall full and half marathons.
Everyone is welcome to Marathon Training Series races: RMRR members, guests, training team members, everyone! The courses are well marked, with mile markers will help you gauge your time. We’ll time your run, and winners of each distance will receive ribbons. We make it easy for you to work on your pace, your nutrition and drinking, and getting everything ready for your big race.
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.
#1: Aug 24 - 10mi & 20mi
#2: Sep 7 - 20k & 30k
#3: Sep 21 - 10mi & 20mi
You are welcome to run 15mi, 25k, or another distance. Just let us know at the start.
RMRR Members receive a 25% discount. Discount taken when you check out. Your membership must be current.
Pick your distance
Running
RMRR Fall Marathon Training - 3 race bundle Short (10m, 20k, 10m)
#1: Aug 24 - 10mi #2: Sep 7 - 20k #3: Sep 21 - 10mi
RMRR Fall Marathon Training - 3 race bundle Long ( 20m, 30k, 20m)
#1: Aug 24 - 20mi #2: Sep 7 - 30k #3: Sep 21 - 20mi
RMRR Fall Marathon Training Series #1 - 10 Mile
RMRR Fall 2023 Marathon Training Series #1 - 20 Mile
Typical race-day weather
Based on 7 years of Open-Meteo archive data for this event's race dates in Thornton, plus the 3 days either side.
The sun rises at 6:19 AM and sets at 7:45 PM local time (MDT) in Thornton on August 23, 2026 — 13h 25m of daylight.
Course
No course map published yet.
The organizer hasn't released a route for this event, and we don't publish guesses. If you're the organizer, send us a GPX file and we'll draw the profile.
Reviews
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Other races near Thornton
Different organizers, within 40 miles, in the next three months
Rmrr Fall Marathon Training Series #2
Rmrr Fall Marathon Training Series #3
I Can 5k
I Ain't Scared (of 5k)
🏃 Plan Your Next Race in Thornton
Find upcoming events by distance:
- Thornton 5K Races 7 races
- Thornton Running Calendar 2026 12 races
Where this page comes from. Race details were last updated on . We re-check listings regularly and again in the week before race day.
- Entries, prices, waves and inclusions — the event's official registration page
- Temperature and humidity — Copernicus ERA5 reanalysis via Open-Meteo (CC BY 4.0)
- Elevation and terrain relief — Copernicus DEM GLO-90, ESA (CC BY 4.0)
- Comparisons and counts — Race Discovery calendar, 12 Thornton events
Spotted something wrong? Tell us and we'll fix it.