Events in Thornton, Colorado | 2026-2027

RMRR Spring Marathon Training Series #1 [rmrr.org] [Register at runsignup.com]
Sun, Mar 29, 2026 at 8:00 AM
Description
RMRR provides low-cost, low-keyed, supported, and timed training races for runners of all abilities. The races are planned to help you prepare for Boston, Colorado, Colfax, and other long spring...
RMRR provides low-cost, low-keyed, supported, and timed training races for runners of all abilities. The races are planned to help you prepare for Boston, Colorado, Colfax, and other long spring races. We make it easy for you to work on your pace, your nutrition and drinking, and getting everything ready for your big race.
- 3/29/26 - 10mi & 20mi
- 4/11/26 - 10mi & 20mi
Sign up for one, or save money and choose the two race bundle. RMRR members get 50% off.

The races begin at 8am, at the Platte River Trailhead Park, at 88th and Colorado, in Thornton. The courses are out-n-back. so we can accommodate almost any distance between 10-20 miles.

Please note that for everyone's safety dogs or running strollers are not permitted on our courses. Thanks for understanding.
10 Miles 20 Miles 40 Miles Marathon Run Trail
Thornton, Colorado, 80229, United States
OpenStreetMap Google Maps

RMRR Spring Marathon Training Series #2 [rmrr.org] [Register at runsignup.com]
Sat, Apr 11, 2026 at 8:00 AM

Description

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...

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.

10 Miles 20 Miles Marathon Run Trail
Thornton, Colorado, 80229, United States
OpenStreetMap Google Maps
Treat Trot - Denver [runsignup.com]
Sat, Jun 13, 2026 at 7:00 AM

Description

Every Registration Includes

Great Swag - designer shirt

Custom medal

Chip-timing with live results and awards

Free photos

Great snacks at the finish line!

Plenty of fun!

Grab your friends and family, you are not going to want to miss this one!

*Youth-based pricing for the 5k/10k, 12 & Under are only $17!

*Register by midnight on Thursday, two Thursdays before race day, to guarantee your shirt!

3.1 Miles 6.2 Miles 15k Run
Thornton, Colorado, 80233, United States
OpenStreetMap Google Maps
Unicorn 5k (North) [runsignup.com]
Sat, Jun 20, 2026 at 8:00 AM

Description

Ready to get off the sofa and gallop around Thornton with some friends? Yeah, you are! Come frolic with us at the Unicorn Runner 5k in Thornton to kick off your summer! You'll earn a sweet tee shirt...

Ready to get off the sofa and gallop around Thornton with some friends? Yeah, you are! Come frolic with us at the Unicorn Runner 5k in Thornton to kick off your summer! You'll earn a sweet tee shirt and a flashy unicorn finisher medal!

It's a 5k distance for all, and whether you walk, trot, canter or gallop, we'll be happy to see you! This event also features a shorter saunter for those not quite ready to enjoy a full 5k! The untimed 3/4 mile run is long enough to get your heart rate up and be a 'real run' without being a sprint!

The Balloon Guy will be back this year- creating balloon creations for all!

Remember to refer your friends and you can earn back up to $20 back from your registration fee. Also - teams of 5 or more each get $5 off their registration. So form a group and get your buddies to join you today!

All the info you need about this event is found on this site - click the menu bar or scroll to the bottom to see a listing of all page links!

Denver Unicorn 5k - April

Highlands Ranch Unicorn 5k - August

1k 3.1 Miles 5k Run Walk
E 108th Ave & Colorado Blvd, Thornton, Colorado, 80233, United States
OpenStreetMap Google Maps
Summer Sizzler- Denver [runsignup.com]
Sat, Aug 08, 2026 at 7:00 AM
Description
Join us for the annual Summer Sizzler 5k/10k/15k! A fun summer event that is perfect for the whole family.

The fun includes -
- Great Swag - designer shirt & custom medal
- Chip-timing with live...
Join us for the annual Summer Sizzler 5k/10k/15k! A fun summer event that is perfect for the whole family.

The fun includes -
- Great Swag - designer shirt & custom medal
- Chip-timing with live results and awards
- Free photos
- Delicious Treats waiting at the finish line
- FREE Shaved Ice!
- Plenty of fun!
Grab your friends and family, you are not going to want to miss this one!

Can't make the race? No problem! We offer a virtual race option where you can run anywhere, at any time, and still earn the fun swag!

*Youth-based pricing for the 5k/10k, 12 & Under are only $17!
- 5k/10k/15K registration includes a custom bib, designer shirt, and a custom finisher medal!
- 1 Mile registration is untimed and includes a custom bib, designer shirt, and a custom finisher medal!
- The kid's dash is a fun, untimed dash for our kiddos ages 10 and under. Registration includes a mini bib, youth-sized shirt, and a specifically crafted medal for our kids' dash event! (If your child wants to run the kid's dash, and doesn't want the SWAG, they are welcome to run with us on race day for free!)
*Register by midnight on Thursday, two Thursdays before race day, to guarantee your shirt!

🏁🏅Create a team, or join an existing team during registration. Once 4 people have registered on that team, all team members will be refunded $5, once ten people register another $5 will be refunded for a total of $10!
1 Miles 3.1 Miles 6.2 Miles Run Virtual
Thornton, Colorado, 80233, United States
OpenStreetMap Google Maps
RMRR September Trophy Series [rmrr.org] [Register at runsignup.com]
Sun, Sep 13, 2026 at 8:00 AM
Description
Rocky Mountain Road Runners holds a monthly Trophy Series in the Denver area. We provide a low-key, low-cost racing environment. Everyone is welcome to run with us!

The 10km race uses a handicap...
Rocky Mountain Road Runners holds a monthly Trophy Series in the Denver area. We provide a low-key, low-cost racing environment. Everyone is welcome to run with us!

The 10km race uses a handicap start system, slow-to-fast, spread over ~30 minutes. This gives everyone a chance to win. We'll use your estimated finish time to assign you a start time with others the same speed.

All 5k racers will start ~15min after the first 10km starters.

Race Day Details

Time: 10k starts at 8:00 am + your handicap.*

5k starts approximately 15min after the first 10k starter.

Show up 30 minutes early to get your tag and warm up.

Location: Riverdale Ballfields, 9830 Riverdale Road, Thornton, Colorado, 80229

Course: Both distances are out-and-back on a mix of paved and smooth gravel.

Parking: Plenty of parking at the park.
- The Trophy Series races use a unique, handicap start and scoring system. 10k racers start from slow to fast giving everyone a chance to win. When you register and pick up your number, we'll help you choose an appropriate start time that fits your estimated time.
5k 10k Gravel Run
9830 Riverdale Road, Thornton, Colorado, 80229, United States
OpenStreetMap Google Maps
I Can 5k [runsignup.com]
Sat, Oct 03, 2026 at 9:00 AM

Description

You CAN 5k. This event is for EVERY ONE. EVERY BODY.

You won't get lost. You won't get forgotten. You'll run (or jog or walk or crawl) a clearly marked 5k course with friendly volunteers pointing the...

You CAN 5k. This event is for EVERY ONE. EVERY BODY.

You won't get lost. You won't get forgotten. You'll run (or jog or walk or crawl) a clearly marked 5k course with friendly volunteers pointing the way! We're going to keep you motivated and safe along the way. When you're done we'll be at the finish line with a huge smile and a high five to celebrate YOU, because YOU CAN 5k!!

Leading up to your race, you'll champion others to donate to one of the local event charities. As your donations grow, so does your swag bag!

3.1 Miles 5k Run Walk
Thornton, Colorado, 80233, United States
OpenStreetMap Google Maps
I Ain't Scared (of 5k) [runsignup.com]
Sat, Oct 31, 2026 at 9:15 AM

Description

Dress up and run spooky and silly at the I Ain't Scared (of 5k) in Thornton! Fun music, Halloween snacks and costumes galore!! This event only comes around once every few years when Halloween lands on a weekend. You don't want to miss it! Every racer gets a T-shirt with GLOW IN THE DARK printing and a FINISHER MEDAL!

3.1 Miles 5k Run
E 108th Ave & Colorado Blvd, Thornton, Colorado, 80233, United States
OpenStreetMap Google Maps
WinterFest 5k & Fun Run [runsignup.com]
Sat, Dec 12, 2026 at 10:10 AM

Description

Kick off the holiday season with a spirited run/walk at Thornton's Carpenter Park. Choose from the chip-timed 5k, or experience the festive atmosphere in a shorter distance in our untimed Fun...

Kick off the holiday season with a spirited run/walk at Thornton's Carpenter Park. Choose from the chip-timed 5k, or experience the festive atmosphere in a shorter distance in our untimed Fun Run/Walk.

Stick around after for the festival, including Ice skating, Holiday Marketplace, Santa visits, and the Heated Beer Garden.

Celebrate the Best of Winter in Thornton, Colorado. You'll enjoy a warm drink at the finish line in your festive collectible mug.

For details about this event, click on the menu options under "Race Info" or scroll to the very bottom of this page for links to other pages on this site.

3.1 Miles 5k Fun Run Run Walk
3498 E 112th Ave, Thornton, Colorado, 80233, United States
OpenStreetMap Google Maps

9 running and walking events in Thornton, Colorado

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Local Clubs & Organizations