History of the Mont Blanc Marathon: from the Cross du Mont-Blanc to today
Written by Victor Michel — history enthusiast and passionate alpinist based in Chamonix. Published August 6, 2026
The Mont Blanc Marathon was born on 1 July 1979 under the name 'Cross du Mont-Blanc', on the initiative of the Club Alpin Français de Chamonix. From 450 runners on a single 23 km format, the race has grown to bring together today more than 10,000 participants across 8 formats, from the children's Mini-Cross to the 90 km.
Key takeaways
- 1 July 1979: first edition under the name Cross du Mont-Blanc, 450 participants
- 2003: the 42 km and 10 km join the program, the race becomes the Mont Blanc Marathon
- 2013-2018: an ultra-long-distance format trialled at 80 km then extended to 90 km
- Today: 8 races, around 10,000 runners each edition
1978: the record that inspired the race
A year before the first edition, in August 1978, Christian Roussel and Jacky Duc completed the entire Tour du Mont Blanc (around 160 km, 5,600 m of elevation gain) in 24h45, fully self-supported. Less than a year later, in July 1979, Roussel improved this time to 21h48 with Jacques Berlie. It was in this spirit of self-supported racing on the massif's trails that the Cross du Mont-Blanc was born a few days later.
1979: the birth of the Cross du Mont-Blanc
On 1 July 1979, on the initiative of the Club Alpin Français de Chamonix chaired by Georges Costaz, together with Christian Roussel, the first edition of the Cross du Mont-Blanc brought together 450 participants on a single 23 km format. The race ran through the Chamonix valley, far from today's trail-running standards: no GPS markings yet, no electrolyte aid stations, an organisation carried by volunteers from the alpine club.
450
participants at the first edition, on 1 July 1979
Marathon du Mont-Blanc
24h45
the time for the full self-supported Tour du Mont Blanc that inspired the race (1978)
Chamonix Mont Blanc Marathon
10,000+
runners today, across 8 races (versus 450 in 1979)
Marathon du Mont-Blanc
2003: the Marathon's turning point
In 2003, the race changed scale: the 42 km and 10 km formats joined the program, and the event took the name Mont Blanc Marathon. That same year, Michel Poletti, René Bachelard and Jean-Claude Marmier took the start of the very first UTMB edition from Chamonix — Poletti would co-found the UTMB with Catherine Poletti that same year. The two races were born and grew in the same Chamonix crucible, before becoming the massif's two distinct benchmark events.
2011-2018: the rise in scale
The program expanded in stages: the Vertical KM in 2011, an ultra-long-distance format trialled at 80 km in 2013 then extended to 90 km from 2018, the Duo Étoilé (team event) and the Young Race in 2015. Since 2010, the organisation has capped the number of participants per race to preserve safety and the on-the-ground experience.
Today: 8 races, 10,000 runners
The Mont Blanc Marathon now brings together 8 formats — from the children's Mini-Cross to the 90 km — and around 10,000 runners each edition in late June. The 42 km was part of the Golden Trail World Series calendar (a circuit created by Salomon) from 2018 to 2024, alongside the world's biggest trail races.
Read next
- → Mont Blanc Marathon: dates, route, pricing — the complete guide
- → Mont Blanc Marathon route: profiles and difficulty by distance
- → Trail training for the Mont Blanc Marathon: 42 and 90 km plan
- → Mont Blanc Marathon or UTMB: which race to choose?
- → UTMB Mont-Blanc: how to enter
- → Which race to choose: UTMB, CCC, TDS, OCC or MCC?
FAQ
When was the Mont Blanc Marathon created?
On 1 July 1979, under the name Cross du Mont-Blanc, on the initiative of the Club Alpin Français de Chamonix. It took its current name in 2003, when the 42 km format was added.
Who created the Mont Blanc Marathon?
Georges Costaz, then president of the Club Alpin Français de Chamonix, and Christian Roussel. Roussel had completed the Tour du Mont Blanc self-supported the previous year (24h45 in 1978, then 21h48 in 1979 with Jacques Berlie) — a feat that directly inspired the race's creation.
How many runners took part in the first edition of the Mont Blanc Marathon?
450 participants, on a single 23 km format, on 1 July 1979. The race now brings together more than 10,000 runners across 8 formats.
Why was the Mont Blanc Marathon called Cross du Mont-Blanc?
That was its original name in 1979, when the race offered only a 23 km format. The name changed in 2003 with the addition of the marathon format (42 km), which gave the event its current name.
When was the 90 km created?
An ultra-long-distance format was first trialled at 80 km in 2013, before being extended to 90 km from 2018 onward. It is today the longest format in the program, excluding the Duo Étoilé.
Does the Mont Blanc Marathon have a link to the creation of the UTMB?
A link of context, not of shared organisation: Michel Poletti, co-founder of the UTMB with Catherine Poletti, ran the very first UTMB edition in 2003 — the same year the Mont Blanc Marathon took its current name. The two races remain separately organised today.
Has the number of runners always been capped?
No. The number of participants per race has been capped since 2010, for safety and terrain-preservation reasons, as attendance kept growing.