27th June 2021


07:00  am


42 km

Difference in height

2730 m +

1700 m -

ITRA Points

2 ITRA points


42 km

The flagship race of the weekend, 2nd stage of the Salomon Golden Trail World Series.

It brings together the best of the discipline who are engaged in a breathtaking battle in a dream setting.

First on the fast and rolling tracks of the first part of the race and then on the steep and technical slopes of the Aiguillette des Posettes, the main difficulty of the course, and then finish facing this incredible panorama of the Mont-Blanc range.

To participate to this race, it’s recommended to have a good mountain race experience, to be comfortable in any ground and to be autonomous for several hours. We draw your attention to the fact that a runner with no ITRA cotation higher than 350 points (check your odds) has very little chance to finish the race. In that case, it’s more recommended to participate in another race of Mont-Blanc Marathon.

Before to register, we strongly recommend that you read the route, profile and estimated passage times to be fully aware of the difficulty of this race.The time barriers indicated take into account possible slowdowns that you may encounter and we strongly advise you to plan your race with a margin over time barriers.

Date: 27th June 2021
Start: 07:00 am
Distance : 42 km
Distance of heights : 2730m+ / 1700m-
ITRA points: 2
(reference : ITRA)

TRAIL in semi-autonomy
Open to ‘Espoir’ Category to upwards
2 300 maximum runners
Maximum time: 9:30 hours
3 full refreshment points
2 light refreshment points

Distances and differences in height are determined by the ITRA (whose organisation is a member) for the Mont-Blanc 42 km. The organisation draws the attention of the riders to the fact that, according to the systems and the settings used, the gpx tracks may give very different results (from 2 407m to 3 192m of elevation gain).

The ITRA presents the precise certification methods it uses on its website. Click here to consult them.

Race bibs distirbution in Place du Mont-Blanc:

  • Thursday 24th June from 09:00 am to 10:00 pm.
  • Friday 25th June from 09:00 am to 06:00 pm.
  • Saturday 26th June  from 09:00 am to 10:00 pm.

During the delivery of the bibs of the Mont-Blanc 42 km, runners will have to present a photo ID and their race bag including all the mandatory equipment for equipment control. Thanks to this, the organisation will be allowed to put a chronometric chip on them. No bib will be given to runners who don’t have their bag including all mandatory equipment.

  • Mobile phone. 
  • A reserve of at least 1 litre of water.
  • Waterproof and windproof jacket with hood (gore tex type) adapted to your size.
  • Survival blanket (140cm x 200cm).
  • Whistle
  • Personal cup.

After a departure from the center of Chamonix (1035m), you will progressively climb the Chamonix valley, passing successively by the hamlets of Bois and Lavancher to reach Argentière (1250m).

Runners bypass the village of Argentière and reach the Planet through the path of rambles before returning to Montroc by briefly taking the municipal road.

After crossing the village of Montroc, you will take the path towards Tré le Champ, from there you will head for the Col des Montets.

You will cross the Col des Montets (1461m) in the heart of the Aiguilles Rouges nature reserve. Then, by the path of the Diligences, you will gain the hamlet of Buet before joining Vallorcine (1260m), nestled at the bottom of a green valley close to Switzerland.

Then begin the progression towards the Col des Posettes (1997m) by a trail starting from the Plan de l’envers.

At the Col des Posettes a light refreshment will awaits you to regain some strength before climbing towards the Aiguillette des Posettes (2201m) where you will be rewarded for your efforts with a sumptuous panorama of the Mont-Blanc massif.

Facing the Aiguille Verte and the Mont-Blanc mountain range, the path follows the ridge of the aiguillette and slowly go down towards the field.

At the chaleyre you will turn on a nice path that will take you back to the Tour, you will cross the village before heading to the glacier of the Tour. After crossing the footbridge over the bism you will take a north path (a little cool in perspective …) towards Montroc, before crossing the hamlets of Frasserands and Tré-le-champ.

At the heart of the Aiguilles Rouges massif, facing the Mont-Blanc range, the path climbs up to La Flégère (1875m).

After a crossing to the beautiful Combe de la Charlanon (1812 m), you will end with a very nice regular trail, which is balcony and open on the Mont-Blanc massif, and wich lead you to Altitude 2000.

The time restrictions indicated below are given as an indication, they may be modified if necessary for the safety of the participants. In case of bad weather, and for security reasons, the organisation keeps the right to stop the event in progress or to change the time barriers. Any decision will be taken by the trail committee.

The arrival of a runner on a time barrier outside the deadline implies his disqualification. The lower right corner of the bib will be “cut” by the person in charge and the runner will be invited to use public transport to return to Chamonix. If the runner wishes to continue the race, his bib number will be taken by the person in charge and the runner will no longer be considered as a participant in the Mont-Blanc 42 km, so he will no longer be under the responsibility of the organiser.

Anyone who doesn’t respect the volunteers in charge of this function will be banned from racing permanently on all events of the Mont Blanc Marathon.

  • Refreshment of Vallorcine (km 17) : starting time of the last wave + 03h00.
  • Refreshment of Tour (km 28) : starting time of the last wave + 05h30.
  • Refreshment of La Flégère (km 37) : starting time of the last wave + 08h05.
In the case of a starting time with waves the time barriers are calculated according to the starting time of the last wave.


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 Marathon Clips 

Réalisation : Coax – 2021.