The Blue Sky Trail Marathon & Half, hosted by Gnar Runners, is Fort Collins, Colorado's premier and only trail marathon, offering a north-south tour of the stunning easternmost hogbacks of the Northern Colorado Front Range. The event features two challenging race distances: the Marathon (approximately 26.7 miles with 3,500 feet of elevation gain/loss) and the Half Marathon (approximately 13.4 miles with 1,800 feet of elevation gain/loss). The courses are nearly 100% dirt and predominantly consist of technical Colorado singletrack, ranging from smooth paths to rocky gardens. With generous cut-off times—nine hours for the marathon and six hours for the half—the race is welcoming to both veteran trail runners and ambitious newcomers.
Races
Race Date:
19 October, 2025
The Blue Sky Trail Half Marathon is a 13.4-mile trail race in Fort Collins, Colorado, featuring scenic singletrack trails and 549 meters of elevation gain through Horsetooth Mountain Park. It offers runners a challenging yet rewarding experience with panoramic views of the Rocky Mountain foothills.
Race Date:
18 October, 2025
The Blue Sky Trail Marathon is a challenging 26.7-mile trail run in Fort Collins, Colorado, featuring approximately 3,500 feet of elevation gain/loss on a course that is 90% technical singletrack. The scenic route takes runners on a north-south tour of the easternmost hogbacks of the Front Range mountains.
Weather based on historical averages.
FAQs
What is the Blue Sky Trail Half Marathon?
How long is the Blue Sky Trail Half Marathon?
Where does the Blue Sky Trail Half Marathon take place?
What is the elevation gain of the Blue Sky Trail Half Marathon?
How can I prepare for the Blue Sky Trail Half Marathon?
How do I choose the right training plan for the Blue Sky Trail Half Marathon?
The Blue Sky Trail Half Marathon is a 13.4-mile trail race in Fort Collins, Colorado, featuring scenic singletrack trails and 549 meters of elevation gain through Horsetooth Mountain Park. It offers runners a challenging yet rewarding experience with panoramic views of the Rocky Mountain foothills.
The Blue Sky Trail Half Marathon is 21km long.
The Blue Sky Trail Half Marathon takes place in Fort Collins, Colorado, United States of America.
The Blue Sky Trail Half Marathon elevation gain is 549 metres, which Runna classifies as a Hilly 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 Blue Sky Trail Half Marathon?
The Blue Sky Trail Half Marathon is a 13.4-mile trail race in Fort Collins, Colorado, featuring scenic singletrack trails and 549 meters of elevation gain through Horsetooth Mountain Park. It offers runners a challenging yet rewarding experience with panoramic views of the Rocky Mountain foothills.
How long is the Blue Sky Trail Half Marathon?
The Blue Sky Trail Half Marathon is 21km long.
Where does the Blue Sky Trail Half Marathon take place?
The Blue Sky Trail Half Marathon takes place in Fort Collins, Colorado, United States of America.
What is the elevation gain of the Blue Sky Trail Half Marathon?
The Blue Sky Trail Half Marathon elevation gain is 549 metres, which Runna classifies as a Hilly race.
How can I prepare for the Blue Sky Trail 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 Blue Sky Trail 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 Blue Sky Trail Marathon?
How long is the Blue Sky Trail Marathon?
Where does the Blue Sky Trail Marathon take place?
What is the elevation gain of the Blue Sky Trail Marathon?
How can I prepare for the Blue Sky Trail Marathon?
How do I choose the right training plan for the Blue Sky Trail Marathon?
The Blue Sky Trail Marathon is a challenging 26.7-mile trail run in Fort Collins, Colorado, featuring approximately 3,500 feet of elevation gain/loss on a course that is 90% technical singletrack. The scenic route takes runners on a north-south tour of the easternmost hogbacks of the Front Range mountains.
The Blue Sky Trail Marathon is 43km long.
The Blue Sky Trail Marathon takes place in Fort Collins, Colorado, United States of America.
The Blue Sky Trail Marathon elevation gain is 1067 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 Blue Sky Trail Marathon?
The Blue Sky Trail Marathon is a challenging 26.7-mile trail run in Fort Collins, Colorado, featuring approximately 3,500 feet of elevation gain/loss on a course that is 90% technical singletrack. The scenic route takes runners on a north-south tour of the easternmost hogbacks of the Front Range mountains.
How long is the Blue Sky Trail Marathon?
The Blue Sky Trail Marathon is 43km long.
Where does the Blue Sky Trail Marathon take place?
The Blue Sky Trail Marathon takes place in Fort Collins, Colorado, United States of America.
What is the elevation gain of the Blue Sky Trail Marathon?
The Blue Sky Trail Marathon elevation gain is 1067 metres, which Runna classifies as a Flat race.
How can I prepare for the Blue Sky Trail 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 Blue Sky Trail 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!
This event listing is for informational purposes only. Runna is not affiliated with, endorsed by, or sponsored by Blue Sky Trail Marathon & Half or Gnar Runners. 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 Blue Sky Trail Marathon & Half website.