Boulderthon Marathon & Half Marathon

Sunday, October 8, 2023 Boulder, CO

Located in northwestern Colorado just 30 miles from downtown Denver, the Boulderthon Marathon and Half Marathon is part of Colorado’s largest Fall race series and is dubbed one of the top-rated marathons in the United States. 

Destination Race, Large Crowds. Voted the #1 Most Beautiful marathon and half marathon in Colorado, and among the most beautiful in the world, Boulderthon brings in over 4000 participants annually. 

Tucked away in the foothills and Valleys of the Rockies, Boulderthon is a destination race for a reason. With awe-inspiring backdrops of the mountains and beautiful trails throughout, the landscape alone makes it worth running. 

Not to mention, Boulder is often named the Happiest Place in the United States, so when you’ve completed the race and run through Downtown Boulder, be sure to celebrate and enjoy the joy of the state! 

The start line for the half marathon is on 21st and Pearl, kicking runners off at 7:30 am sharp along Pearl Street. Along the Pearl Parkway, runners will intersect Cotton Lake and Valmont Road before turning left onto 61st Street.

At mile 5 it’s onto 63rd Street before turning around at mile 6. Instead of backtracking, however, it’s a turn onto Jay Road, then onto 57th Street and Independence Road at mile 8. 

Through Hayden Lake, runners persist through the foothills until they reach Mapleton Avenue, the final destination before reaching the finish line.

With a 7500 participant cap, Boulderthon is truly one for the books. Spectacular by every definition, all participants can expect a 5-star experience from beginning to end. For the highest achievers, this event offers cash prizes, finisher’s awards, and 50% off next year’s registration! 

Race Weather & Climate

Boulder is located in north-central Colorado, approximately 30 miles northwest of downtown Denver, making it a vibrant city nestled in the foothills of the Rocky Mountains.

On October 8 in Boulder, Colorado, you’ll experience the beauty of the fall season. High temperatures tend to hover around 68°F, offering a crisp and refreshing atmosphere for outdoor activities. As night falls, temperatures drop to around 42°F, indicating the onset of cooler autumn nights. Precipitation remains limited, with an average of just 0.6 inches of rainfall, allowing for enjoyable outdoor pursuits in the city and surrounding areas.

Boulderthon Marathon & Half Marathon Race Results

2023 Boulderthon Marathon & Half Marathon Race Results

Boulderthon Marathon & Half Marathon Course Map

Starting Time

The half marathon start time is 7:30 AM.

The course closes at 2:00 PM.


To reserve your spot in the 2023 Boulderthon Marathon & Half Marathon, you can use the registration link here.

Race Fees

  • There is a $169.00 fee for the full marathon.
  • There is a $159.00 fee for the half marathon.
  • There is a $64.00 fee for the 10K.
  • There is a $59.00 fee for the 5K.
  • There is a $24.00 fee for the kids run.

Boulderthon Marathon & Half Marathon Race Website

Boulderthon Marathon & Half Marathon Website

See more races in: October, Colorado