Come join us for a race around the entirety of beautiful Lake McIntosh! This 3.5 mile race is a half paved/half dirt course surrounded by wonderful mountain views, vast farmlands, and beautiful aquatic wildlife! Gather at Dawson Neighborhood park near the pirate ship playground where you will find an assortment of vendors, music, games, and fun! All are welcome to participate in this awesome event! Doggos are encouraged to participate!
! NEW ADDITION ! We are so excited to announce the Kids Dash! Please bring your kiddos to enjoy a mad dash to the finish line near the Pirate Ship Playground at Dawson Park!
Founded in 2011, over 10,000 B Strong Riders have raised over $5 million to fund the B Strong Center for Integrative Care at Boulder Community Health and support other local cancer charities.
Event T-Shirt & Jersey:
[B Strong 2026 T Shirt.jpg] [b48c1cff-0f1d-4a09-b7d4-f1d920d563a8.jpg]
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!
parkrun is such a simple concept: turn up every Saturday and volunteer, walk, jog or run 5k.
NO Race Day Registrations
Fun for all, from newcomers of any age racing for the first time to veteran competitors looking to test their fitness, all in a friendly, welcoming environment.
Held at the Historic Potts Field, home of the University of Colorado Track & Field Team, the facilities offer the full range of track and field events and is one of the only meets in Colorado that offer a chance to run the Steeplechase or throw the javelin.
If you've been wanting to try a track race and run in the footsteps of CU stars such as Jenny Simpson, Emma Coburn, Joe Klecker, Val Constien, Dathan Ritzenhein, Alan and Shayne Culpepper, and Kara and Adam Goucher, now is your chance!
Eat. Run. Adopt.
Join us for Berthoud’s first-ever community-driven 10k!
In partnership with Berthoud Pet Supply, this isn’t just a race—it’s a moving feast with a mission. A portion of race registration proceeds will go to Scroungy Dogs and Pretty Pups Rescue This community race and expo is designed to support Scroungy Dogs and Pretty Pups Rescue, a local 501(c)(3) non-profit dedicated to rescuing and rehoming dogs and cats throughout Northern Colorado.
Inspired by the spirit of the famous Taco Bell 50k, we are hitting the pavement to celebrate the heart of our town: our local cuisine, and small businesses. Runners will run around town stopping at set up food aid stations with a sample of the local restaurants food. They will wear a wristband that will be hole punched to show they completed eating their samples. They can collect all samples and eat them at the finish but need to hole bunch their wristband to confirm they made the stops.
Prizes for the overall winner are BOLDERBoulder 2027 entrance + cash prize. Runners up in men, women, kids, seniors get a gift basket with local items from local businesses.
August 8, 2026 Come Run, Come All to Dirt Circus Boulder! The Dirt Circus returning to Boulder, Colorado. Dirt Circus is a series of free community events organized by UltraSignup to celebrate local races, and race directors. We are bringing together the local running community to share everything we love about trail running. The one-day festival will highlight local races, run clubs, brands, and other local businesses. The event includes a social run, food, a raffle with tons of prizes, camaraderie, and so much more. Come and join us under the big top.For information on Dirt Circus events in other cities check out dirtcircus.ultrasignup.com + join our online community on Facebook! Local Store Partner This event is possible because of the local partnership of Runners Roost in Boulder. Stop on in for all the running shoes, apparel, and other gear you could need. Dirt Circus Boulder Partners Dirt Circus is a party to bring together the whole running community, not just runners, but also race
companies, coaches, nutritionists, and running brands. See below for some of the partners who will join us in Boulder! Are you a race director, run club, or other local run business that wants to be a part of the event? Fill out this form, we'd love to hear from you.SponsorsRace Companies Onsite VendorsAltra • Asics • Brooks • Buff • Elite Massage • Hoka • Nathan • Neversecond • On • Precision Fuel & Hydration • La Sportiva • Mount to Coast • Salomon • Saucony • Topo Athletic • and more!Run ClubsBlack Men Run + TURF Denver • Coffee Run Club Boulder • Denver Beer Co’s South Downing Run Club • Denver Black Girls Run Club • Roxborough Running Club • and more! Volunteers We LOVE our volunteers - and could use additional help with Runner-Check In, with Leading and Sweeping our group runs, and during the Raffle! If you are interested check out the Volunteer Link and we will make sure you get hooked up with extra swag for your support! And don't worry about missing out, all
volunteers will be included in the run and festivities if interested! Event Details Saturday August 8, 2026We are a CUPLESS event, so please bring your bottles/cups water refills + is supplying electrolytes to keep you hydrated! As much as we love our fur babies, NO DOGS allowed (except service animals) - thanks for understanding!7:00am - Group Run Check-inat: Runners Roost BoulderGive yourself time to check in, mingle, demo shoes, and get ready to run. Participants will receive a sweet UltraSignup branded "Shoe Bag Lite" upon check-in (while supplies last)! And to help ramp up the fun, we are partnering with for our face decorating, glitter station!8:00am-8:30am - Group Run Starts We will send runners out in waves every few minutes! Enjoy a casual 4.5 mile or 10k run with friends from the local run community!9:00-9:30am - Return from Group Run for the FestivitiesEnjoy food, beverages, and the Dirt Circus Expo!10:00am-12:00pm - Raffle, Expo, & Social ConnectionsGet excited for raffle
prizes from brand partners, race entries, and cool swag & apparel! We'll have brand booths and tables set up around when you return from your run, whatever distance you chose. Talk to race directors, learn about local races, mingle with friends, learn about running shoes and apparel products, and maybe test out some hydration and nutrition brands!Preorder Your Original Dirt Circus T-Shirt! Each city on the tour gets its own exclusive design—only available for purchase during registration! Don’t miss out on the Boulder edition, with preorders closing Sunday, July 19, 2026. Plus, explore even more Dirt Circus swag available for purchase at checkout and see more UltraSignup gear via the store link below. Routes What is Dirt Circus? Did you know that there are thousands of small local trail running events across the United States each year? Our goal is to connect runners with races and with one another, to highlight race directors, running stores, coaches, and the other local businesses that
make up the fabric of our trail running community. The best way we know how to do that is by going for a run together. This sport is a little wild and we like it that way, so come join the Dirt Circus with us.Meet with race directors, find your next event, run with friends, win prizes and more. Think of it as a live and in-person version of ultrasignup.com, but even more fun.Why a Circus? Once upon a time, ultrarunning looked a little different. The sport has its roots in pedestrianism, where people would gather under the big top and walk and run for sport. Bets were made, the limits were pushed, and popularity soared. So come entertain yourselves with us, under the metaphorical big top. UltraSignup Store Shop UltraSignup gear and apparel in the UltraSignup Store. Event's current local time: 2:13 AM MT
Founded in 1979, the Eldorado Run for the Cure is the longest operating charitable footrace in the State of Colorado. All proceeds from the annual four-mile run benefit the Colorado Cancer Foundation's life saving work, from funding oncology research at the University of Colorado's (CU) Division of Medical Oncology to aiding patients at the CU Hospital in Aurora, CO.
Each year, the run has developed and grown, and in 2023 a new course was introduced, routing participants along the scenic South Boulder Creek, which winds through the high cliff walls of historic Eldorado Canyon.
As the summer mornings start to cool, join us for a fantastic end-of-season celebration at our 14th annual Runapalooza! From our new venue at Colorado Tap House, you'll have the chance to tackle relatively gentle 5K and 10K courses that go along the acclaimed Ralston Creek Trail, taking you through shady, creekside beaty along Arvada's picturesque open spaces and charming golf course communities. Or our challenging half marathon course that combines the beauty of the Ralston Creek Trail with the challenging Blunn Reservoir loop with its gorgeous Denver and Front Range views. This event, paired with its Endless Series' counterpart Mardi Crawl, offers a can't-miss opportunity to experience the best of what Colorado has to offer!
August may be hot...but still a great time to run, and we hope you'll come join the runners of RMRR. We'll run our August 5k on the Highline Canal around DeKoevend Park. As always, everyone is welcome.
For August, we use a mass start rather than our standard handicap start system.
Race Day Details
Date: Friday August 4th
Time: 6:30 pm start. Show up 30 minutes early to walk from your car, get your registration info, and warm up.
Distance: 5k.
Course: Race runs on the crusher/fine dirt Highline Canal around DeKoevend Park.
Course on Strava: https://www.strava.com/segments/22931643
Location: DeKoevend Park in Centennial. We run from the pavilion behind the Goodson Recreation Center.
Google Parking Link: Goodson Rec Center Parking. Park towards the far W end of the lot.
Stick around after for our potluck BBQ. RMRR provides the grillables and non-alcoholic drinks. We ask everyone to bring a salad, side dish, or dessert to share.
Run. Support. Celebrate.
Join us for the 7th Annual Arapahoe Warrior 5K and support the Arapahoe Warrior Cross Country Team!
With $10 from every registration going directly to the Arapahoe Cross Country Booster Club, your participation makes a real difference for these hardworking athletes.
Enjoy a scenic run through the beautiful residential streets of Centennial on a measured, clearly marked course—perfect for runners, joggers, and walkers alike.
Post-Race Pancake Breakfast
After crossing the finish line, celebrate with a delicious pancake breakfast by Flippin’ Flap Jacks—complete with sausage and refreshing orange juice—free for all registered participants.
Custom T-Shirts
Add a race T-shirt to your registration for just $14.
Order by July 14th to guarantee yours.
Shirts are fitted—size up if you prefer a looser fit.
Finisher Medal & Awards:
Top 3 in each age group earns a custom 3.5” die-cast medal with a unique lanyard!
Top finishers will also be recognized:
Overall Winners
🏆 Male Overall Winner
🏆 Female Overall Winner
Age Group Awards – Top 3 in Each
10 & Under – Boys/Girls
11–12 – Boys/Girls
13–14 – Boys/Girls
15–19 – Boys/Girls
20–29 – Male/Female
30–39 – Male/Female
40–49 – Male/Female
50–59 – Male/Female
60–69 – Male/Female
70+ – Male/Female
That’s 62 total custom medals up for grabs!
Race Day Details
📅 Race Day: Saturday, August 8th
⏰ Start Time: 8:00 AM
📍 Location: Arapahoe High School – 2201 E Dry Creek Rd, Centennial, CO 80122
Packet Pickup & Registration
Friday, August 7th – Pre-Packet Pickup: 9:00 AM–11:00 AM at Arapahoe High School
Race Day Registration – Opens at 7:00 AM ($40)
Parking
Available at the high school and nearby neighborhoods.
Course Info
🏃 Course Type: Out-and-back
📈 Elevation Gain: 109 ft
📉 Elevation Loss: 89 ft
⬇️ Min Elevation: 5,575 ft
⬆️ Max Elevation: 5,665 ft
Join us August 5, 12, 19 & 26 for a fun series of shorter midweek trail races.
Our goal is to offer a fun, low-key series of races designed to give newer trail runners an opportunity to dip their toes into the trail racing waters, and to offer more experienced trail racers a chance to sharpen their speed on shorter, quicker courses. All races will start at 6:00pm, ranging in distance from 5k to 12k. Results will be tabulated according to chip times, with series points awarded for each race. Top series finishers will earn unique awards.
We'll have a wide selection of vintage Gnar race shirts, and all registrants are welcome to their pick to call their own.
After each race, we will be providing pizza with support from the Fort Collins Running Club and beverages with support from New Belgium Brewing.
Race dates and distance are as follows:
August 5: Flat and Fast Eltuck Valley 5k (250′ elevation gain)
August 12: Into the Hills Eltuck 5k (700′ elevation gain)
August 19: Into the Hills Eltuck 10k (1,700′ elevation gain)
August 26: Flat and Fast Eltuck Valley 12k (500′ elevation gain)
Start: Lory State Park, Eltuck Picnic Area, Fort Collins, Colorado
Distance: 5k - 12k
Dates: August 2026
Time: 6:00pm
Cost:
Thru 6/30: $25 each race or $80 for the series
7/1 & After: $30 each race or $100 for the series
Special pricing of $10/race for Ages 17 & Under. Price change will be automatically applied based on registrant's Date of Birth before final checkout on RunSignup.
All race participants are welcome to a free vintage shirt from previous Gnar races (your choice and as available). Awards will be given out at the end of the series to top points scorers.
We acknowledge and respect those who experience their gender identity in ways outside of the traditional male/female dichotomy, and are trying our best to provide non-binary opportunities in both the registration and results to reflect that. For the purposes of awards, non-binary runners will be eligible in their birth gender pool.
Race dates and distance are as follows. Click the race link to view the course map
Trail Sisters Approved
Transfer Credit & Distance Change Policy
If you are not able to race, we can offer a 75% race transfer credit that can be applied to any future Gnar Runners race (valid for 12 months). We can also directly transfer your entry to another race in the series for the same year, assuming the new race is not sold out. Transfers/Credits can be requested any time up until 72hrs before the start of each race in the series. To request a transfer credit please Contact Us.
Cancellation Policy
With the exception of waitlist transfers, entries are non-refundable and non-transferable. In the event the race is cancelled due to extreme weather, fire, disease or for some other unforeseeable event, we cannot offer refunds or credits.
Rules
Purposeful littering is prohibited and will result in an immediate disqualification.
Stay on the trail. No bushwhacking or short cutting. In case of wet trail conditions, please run through any muddy sections to avoid widening the trail. Yield to pedestrian and horses. Mountain bikers should yield to runners, but please use common sense in all circumstances.
If coming up on a slower runner or regular park user while on trail, please give an early verbal notice that you are approaching and wait for the hiker/runner to step off to the side before passing.
No mechanical aid (poles, traction devices, etc.) unless approved by race staff prior to the race for a specific reason.
Dogs are not allowed on the course with runners.
If you do not have an annual Colorado State Parks Pass or a pass with your vehicle registration, you will need to purchase a day pass ($10) when you enter the park.
Parking will be at the Eltuck Picnic Area until filled, after which we will direct cars to the nearby Spur Road. For those parking on the Spur Road, it will be a short walk to the start.
Bibs will be available for pick up at the race start from 5:00pm. Chips will be pre-attached to your bib. If you are running multiple races in the series, please keep your bib to reuse in your next race(s).
Aid, Etc
These are no frills, basic races. There is no on-course aid.
There are two permanent toilets at the start/finish of each race. Additionally, the Valley 5K goes past park restrooms at the 0.25 and 1.5mi marks; the Hilly 5K & 10K go past a park restroom at the 0.25mi mark, and the Valley 12K goes past park restrooms at 0.25, 3.8, 6.1 & 6.3mi marks.
The Splash Mash Dash Kids Triathlon is perfect for kiddos looking for a way to "TRI" the sport of triathlon or tune up their skills for a larger race. The race will offer kids a safe and fun environment for racing.
To encourage participation and enjoyment for all, The Splash Mash Dash Kids Triathlon is a non-timed event. However, we do have awesome finisher medals that look just like the medals they've seen parents collect over the years! We encourage every child to do their best and practice racing in a supportive environment. We encourage parents to manually time their child if they are interested in a time for their race.