The Boulderthon is a popular marathon event held annually in Boulder, Colorado, offering a marathon, half marathon, and 5K race options. The course takes runners through the scenic streets of Boulder, with breathtaking views of the Flatirons and the surrounding Rocky Mountains. Known for its challenging course, the race offers an opportunity to experience both the natural beauty and vibrant atmosphere of Boulder, a city famous for its outdoor lifestyle. The Boulderthon attracts a diverse range of participants, from elite athletes to casual runners, all united by their love of the outdoors and running. With strong community support, great organization, and a focus on wellness, the Boulderthon is a highly anticipated event in the region’s running calendar.
Races
Marathon
Half Marathon
10km
5km
Race Date:
28 September, 2025
The Boulder Marathon, organized by Stronger Faster Boulder Co, offers a 26.2-mile scenic route through Boulder, Colorado, on September 28, 2025. With 293 meters of elevation gain, this Boston Marathon-qualifying race challenges runners with rolling terrain and stunning mountain views.
Race Date:
28 September, 2025
The Boulder Half Marathon, part of the Boulderthon event, takes place on September 28, 2025, offering runners a 13.1-mile course with an elevation gain of 62 meters. Organized by Stronger Faster Boulder Co, this route combines manageable terrain with the scenic charm of Boulder.
Race Date:
28 September, 2025
The Boulder 10K, organized by Stronger Faster Boulder Co, offers a fast 6.2-mile course on September 28, 2025, starting in downtown Boulder. With just 25 meters of elevation gain, this race is perfect for runners seeking a personal best or a quick, scenic run.
Race Date:
28 September, 2025
The Heart to Heart 5K, part of the Boulderthon event, invites participants to a 3.1-mile race through downtown Boulder on September 28, 2025. Organized by Stronger Faster Boulder Co, this course features a slight 37-meter elevation gain, making it fun and accessible for all.
Weather based on historical averages. Route data provided by Strava, based on last year's race.
FAQs
What is the Boulder Marathon?
How long is the Boulder Marathon?
Where does the Boulder Marathon take place?
What is the elevation gain of the Boulder Marathon?
How can I prepare for the Boulder Marathon?
How do I choose the right training plan for the Boulder Marathon?
The Boulder Marathon, organized by Stronger Faster Boulder Co, offers a 26.2-mile scenic route through Boulder, Colorado, on September 28, 2025. With 293 meters of elevation gain, this Boston Marathon-qualifying race challenges runners with rolling terrain and stunning mountain views.
The Boulder Marathon is 42km long.
The Boulder Marathon takes place in Boulder, Colorado, USA.
The Boulder Marathon elevation gain is 293 metres, which Runna classifies as a Rolling race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Boulder Marathon?
The Boulder Marathon, organized by Stronger Faster Boulder Co, offers a 26.2-mile scenic route through Boulder, Colorado, on September 28, 2025. With 293 meters of elevation gain, this Boston Marathon-qualifying race challenges runners with rolling terrain and stunning mountain views.
How long is the Boulder Marathon?
The Boulder Marathon is 42km long.
Where does the Boulder Marathon take place?
The Boulder Marathon takes place in Boulder, Colorado, USA.
What is the elevation gain of the Boulder Marathon?
The Boulder Marathon elevation gain is 293 metres, which Runna classifies as a Rolling race.
How can I prepare for the Boulder Marathon?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Boulder Marathon?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Boulder Half Marathon?
How long is the Boulder Half Marathon?
Where does the Boulder Half Marathon take place?
What is the elevation gain of the Boulder Half Marathon?
How can I prepare for the Boulder Half Marathon?
How do I choose the right training plan for the Boulder Half Marathon?
The Boulder Half Marathon, part of the Boulderthon event, takes place on September 28, 2025, offering runners a 13.1-mile course with an elevation gain of 62 meters. Organized by Stronger Faster Boulder Co, this route combines manageable terrain with the scenic charm of Boulder.
The Boulder Half Marathon is 21km long.
The Boulder Half Marathon takes place in Boulder, Colorado, USA.
The Boulder Half Marathon elevation gain is 61.87 metres, which Runna classifies as a Flat race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Boulder Half Marathon?
The Boulder Half Marathon, part of the Boulderthon event, takes place on September 28, 2025, offering runners a 13.1-mile course with an elevation gain of 62 meters. Organized by Stronger Faster Boulder Co, this route combines manageable terrain with the scenic charm of Boulder.
How long is the Boulder Half Marathon?
The Boulder Half Marathon is 21km long.
Where does the Boulder Half Marathon take place?
The Boulder Half Marathon takes place in Boulder, Colorado, USA.
What is the elevation gain of the Boulder Half Marathon?
The Boulder Half Marathon elevation gain is 61.87 metres, which Runna classifies as a Flat race.
How can I prepare for the Boulder Half Marathon?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Boulder Half Marathon?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Boulder 10km?
How long is the Boulder 10km?
Where does the Boulder 10km take place?
What is the elevation gain of the Boulder 10km?
How can I prepare for the Boulder 10km?
How do I choose the right training plan for the Boulder 10km?
The Boulder 10K, organized by Stronger Faster Boulder Co, offers a fast 6.2-mile course on September 28, 2025, starting in downtown Boulder. With just 25 meters of elevation gain, this race is perfect for runners seeking a personal best or a quick, scenic run.
The Boulder 10km is 10km long.
The Boulder 10km takes place in Boulder, Colorado, USA.
The Boulder 10km elevation gain is 25 metres, which Runna classifies as a Flat race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Boulder 10km?
The Boulder 10K, organized by Stronger Faster Boulder Co, offers a fast 6.2-mile course on September 28, 2025, starting in downtown Boulder. With just 25 meters of elevation gain, this race is perfect for runners seeking a personal best or a quick, scenic run.
How long is the Boulder 10km?
The Boulder 10km is 10km long.
Where does the Boulder 10km take place?
The Boulder 10km takes place in Boulder, Colorado, USA.
What is the elevation gain of the Boulder 10km?
The Boulder 10km elevation gain is 25 metres, which Runna classifies as a Flat race.
How can I prepare for the Boulder 10km?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Boulder 10km?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Heart to Heart 5km?
How long is the Heart to Heart 5km?
Where does the Heart to Heart 5km take place?
What is the elevation gain of the Heart to Heart 5km?
How can I prepare for the Heart to Heart 5km?
How do I choose the right training plan for the Heart to Heart 5km?
The Heart to Heart 5K, part of the Boulderthon event, invites participants to a 3.1-mile race through downtown Boulder on September 28, 2025. Organized by Stronger Faster Boulder Co, this course features a slight 37-meter elevation gain, making it fun and accessible for all.
The Heart to Heart 5km is 5km long.
The Heart to Heart 5km takes place in Boulder, Colorado, USA.
The Heart to Heart 5km elevation gain is 37 metres, which Runna classifies as a Rolling race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Heart to Heart 5km?
The Heart to Heart 5K, part of the Boulderthon event, invites participants to a 3.1-mile race through downtown Boulder on September 28, 2025. Organized by Stronger Faster Boulder Co, this course features a slight 37-meter elevation gain, making it fun and accessible for all.
How long is the Heart to Heart 5km?
The Heart to Heart 5km is 5km long.
Where does the Heart to Heart 5km take place?
The Heart to Heart 5km takes place in Boulder, Colorado, USA.
What is the elevation gain of the Heart to Heart 5km?
The Heart to Heart 5km elevation gain is 37 metres, which Runna classifies as a Rolling race.
How can I prepare for the Heart to Heart 5km?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Heart to Heart 5km?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
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Sport:
Running
Tags:
Dog Friendly
This event listing is for informational purposes only. Runna is not affiliated with, endorsed by, or sponsored by Boulderthon: Boulder Marathon presented by PUMA or BOLDERBoulder. All event details are based on publicly available information and are provided solely to help users discover running events. Runna does not use any official logos, images, or proprietary content from this event or its organiser. Any trademarks or names mentioned are used descriptively to identify the event in a factual manner. For the most accurate and up to date information (including to register or purchase an entry to the event), please visit the Boulderthon: Boulder Marathon presented by PUMA website.
