9 running and walking events in Thornton, Colorado

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!

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.

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!

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.