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Boulderthon – Boulder Marathon
Race Details:
- Location: Boulder, CO, USA
- Race Date: 09/27/2026
- Race Distances: Full Marathon, Half Marathon
What This Race Counts Toward:
Boston: Yes
World Marathon Majors: Yes
Boulderthon – Boulder Marathon Description
Boulderthon starts and finishes in downtown Boulder, Colorado, sending runners out past the Flatirons and near Boulder Reservoir before returning for a finish on the historic Pearl Street Mall. A redesigned course cuts elevation gain by roughly 40 to 50 percent compared to prior years, trading some climbing for more of Boulder’s back roads and mountain views. Held each September as part of the city’s largest fall race weekend, the marathon is a Boston Marathon Qualifier and has grown quickly since launching, selling out every year. A half marathon, 10K, and 5K run the same weekend for runners chasing a shorter distance.
Always check the official race website for the most accurate and up-to-date race information and logistics.
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Boulderthon – Boulder Marathon Additional Details:
Every finisher medal at Boulderthon is made from 100% recycled materials, part of a design that’s refreshed each year through a contest open to runners rather than dictated by organizers alone. At the finish, Athletic Brewing Company hands out complimentary cans of its award-winning non-alcoholic beer, a celebration built around community and mindfulness rather than the usual finish-line kegs. Aid stations throughout are well-stocked with water, electrolytes, and portable restrooms, giving the race the feel of a much bigger event despite its smaller-town charm. With the after-party spilling onto Pearl Street’s shops and restaurants, race day here blends easily into a full day of celebrating in downtown Boulder.
Course Information
Profile: Hilly
Type: Loop
Surface: Road/Pavement
Pace Groups: Yes
Time Limit: 6 hours
# of Finishers
Half Marathon: 2,000 to 3,000
Marathon: 1,900 to 2,000
Elevation Details
Elevation Gain: Unknown
Elevation Loss: Unknown
Average Temperature
- Low: 45°F
- High: 72°F
Train Smarter for Race Day
A great race starts long before the starting line. Whether you’re chasing your first finish or hunting a new PR, a structured training plan takes the guesswork out of race prep — building your fitness, your confidence, and your mileage at the right pace for you.
Explore plans for every distance and experience level, from your first 5K to your next ultra.
Things to Do in Boulder, CO, USA
Make the most of race weekend — here’s how to fill the time before and after you cross the finish line.
Shopping
Pearl Street Mall
Browse the brick-paved Pearl Street Mall, Boulder’s historic pedestrian heart, for shops, galleries, and street performers — an easy, flat, car-free stroll after race weekend.
Outdoors & Trails
Boulder Creek Path
Walk or bike a flat, scenic stretch of the Boulder Creek Path, part of 300 miles of trails winding through the city’s open space — easy on tired legs after race day.
Sports & Entertainment
Folsom Field
Cheer on the CU Buffs at Folsom Field, one of college football’s most scenic stadiums with the Flatirons as a backdrop — a relaxed, seated way to spend a Saturday.
Food & Drink
Boulder Beer Trail
Sample craft beer along Boulder’s Beer Trail, home to more than a dozen breweries scattered around town — a relaxed, low-key way to celebrate the finish line.
Landmark
CU Boulder’s Old Main
Stroll the architecturally stunning CU Boulder campus, including Old Main, the university’s oldest building dating to 1876 — an easy, flat walk through historic grounds after race day.
Museums & History
Fiske Planetarium
Catch a fulldome show beneath the 65-foot dome at Fiske Planetarium, the largest planetarium between Chicago and Los Angeles — a relaxed, seated, indoor rest-day option.
Scenic Drives & Viewpoints
Flatirons at Chautauqua Park
Take in the iconic Flatirons, Boulder’s massive sandstone slabs, from the trails around Chautauqua Park — a scenic, choose-your-distance option for tapering or recovering runners.
Arts & Culture
Boulder Dushanbe Teahouse
Sip tea inside the hand-carved Boulder Dushanbe Teahouse, shipped piece-by-piece from Boulder’s sister city in Tajikistan — a relaxed, low-impact way to spend an afternoon.
Hotels & Lodging Near the Boulderthon – Boulder Marathon
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Boston Qualifier: Yes