Marathon du Mont-Blanc is a 42km ultra marathon in Chamonix, France. Distance: 42km. Elevation: 2,600m D+. Difficulty: moderate (Challenge Rating 47/100). DNF rate: 10%. Time limit: 10h. Surface: trail. Established 2003.
Marathon du Mont-Blanc
Chamonix, Haute-Savoie, France
"A mountain marathon beneath Mont Blanc. 42km with 2,600m of climbing from the world's trail running capital."
Chamonix's mountain marathon — 42km with 2,600m of climbing in the shadow of Mont Blanc during UTMB week.
The Course
A mountain marathon loop from Chamonix with 2,600m of climbing. The course climbs to the Aiguillette des Possettes at 2,201m with views of Mont Blanc before descending back to Chamonix. Runnable trails mixed with steep mountain terrain.
mountainous
loop
5
4
Runner Experience
Standard aid station support with food, drinks, and basic medical assistance at regular intervals.
A legendary finish line atmosphere. Marathon du Mont-Blanc is a bucket-list race with celebrations that match its reputation.
Race Day Weather
16°C
6° – 26°
55%
30%
Chamonix summer — warm in the valley, cool at altitude. Afternoon thunderstorms possible. Generally pleasant.
Stats & Records
2003
2,000
06:30:00
03:30:00
Kílian Jornet (2013)
04:12:00
Maude Mathys (2019)
Entry
€80
November
instant
Lore & Trivia
The Trail du Mont Blanc follows sections of the famous Tour du Mont Blanc hiking route — the same paths that inspired the creation of UTMB. The shorter format (various distances) makes the Mont Blanc massif accessible to runners who aren't ready for the full UTMB loop. The views are the same: glaciers, granite peaks, and the Chamonix Valley spread below.
- ▸ This race kicks off UTMB week in Chamonix — the marathon-distance appetizer before the main events.
- ▸ Kílian Jornet's 3:30 course record averages under 5 min/km over 42km with 2,600m of climbing.
- ▸ The views of Mont Blanc from the Aiguillette des Possettes are among the best in the valley.
- ▸ Despite being marathon distance, the 2,600m of elevation makes this equivalent to a much longer flat race.
- ▸ Established in 2003.
The trail that inspired UTMB — hiking paths around Mont Blanc that became the most famous running course on earth.
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Frequently Asked Questions
How long is Marathon du Mont-Blanc? +
Marathon du Mont-Blanc is a 42km (42km) ultra marathon with 2,600m of elevation gain. The course is loop on trail terrain.
How hard is Marathon du Mont-Blanc? +
Marathon du Mont-Blanc is rated moderate with a Challenge Rating of 47/100 (Challenging). The DNF rate is 10%. Runners have 10 hours to finish.
How do I enter Marathon du Mont-Blanc? +
Entry is by lottery. Entry costs €80. with a maximum of 2500 starters.
What is the weather like at Marathon du Mont-Blanc? +
Average temperature is 16°C (range 6°C to 26°C) with 55% humidity and a 30% chance of rain. Chamonix summer — warm in the valley, cool at altitude. Afternoon thunderstorms possible. Generally pleasant.
Are crew and pacers allowed at Marathon du Mont-Blanc? +
No crew access is permitted. Pacers are not allowed. Mandatory gear is required.
What is the course record for Marathon du Mont-Blanc? +
The men's course record is 03:30:00 set by Kílian Jornet in 2013. The women's course record is 04:12:00 set by Maude Mathys in 2019.
What is the average finish time for Marathon du Mont-Blanc? +
The average finish time is 06:30:00. About 2,000 runners finish each year. The DNF rate is 10%.
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