marmotte sur un rocher

A responsible, sustainable and local Marathon

Since the creation of the Cross du Mont-Blanc in 1979, the Club des Sports de Chamonix has been working to offer quality races while limiting their impact on the environment. With this in mind, a number of initiatives have been put in place and continue to be implemented.

Our approach

With a view to reducing the environmental impact generated by our races, we try as far as possible to place our refreshment points close to a water source, and in a location that allows the facilities to be supplied with electricity.

Bottles of still and sparkling water have been completely removed from the refreshment stands. The organization has purchased 1000L tanks. The technical team makes sparkling water from electrolyte tablets. This water is distributed by taps.

Following on from this idea, eating local produce is a matter of course for us. Our cheese comes from the Montroc farm and the Vallorcine farm.

When purchasing our products, we try to give priority to those with minimalist packaging, purchases in large quantities, etc., to reduce our waste production.

We also limit the use of personalized administrative procedures on single-use paper, particularly at the bib distribution desk, where the system is optimized to reduce paper consumption to a minimum.

In collaboration with the SITOM (the valley's waste sorting center), waste sorting is encouraged through eco-collections at public gathering points and ensured at our refreshment stands by our teams of volunteers who are very attentive to this issue (recovery of bottle tops for the construction of wheelchairs for the disabled, etc.).

Our teams of closers are in charge of cleaning all the trails after the runners.

Chamois dans la nature
Bénévole servant de l'eau
Vue Mer de glace
Coureur se servant de l'eau
bouquetin en noir et blanc

To limit the use of individual vehicles during the event, we have set up several shuttle systems.

  • The first enables runners to be picked up and transported to their starting lines.
  • The second allowed those accompanying the runners to follow them throughout the valley without using their personal vehicles.

The frequency of shuttles has been optimized as far as possible to meet the expectations of accompanying persons.

In keeping with the idea of reducing the use of vehicles, members of the organization have access to a fleet of electric bikes, which they use whenever possible.

Runners during their races, as well as the public in the crowded areas, benefit from the installation of dry toilets containing wood shavings and producing exclusively biodegradable waste.

Several measures are still under consideration, and we will keep you informed of their future implementation.


This year, after an in-depth study of the event's carbon footprint, we came to the conclusion that the biggest share of emissions comes from participant transport. We offered runners whose modes of transport are the least respectful the opportunity to make a donation to an environmental project to offset their carbon emissions from the event. As soon as they register, and at any time before the race, runners can make a voluntary donation.

La proposition est un succès car plus de 2000 coureurs ont participé, pour un total récolté de 5000€. Le Club des Sports s’engage à reverser l’intégralité de cette somme pour des projets environnementaux.

The proposal was a success, with over 2,000 runners taking part, raising a total of €5,000. The Club des Sports is committed to donating the entire amount to environmental projects.

After extensive research, we have selected two associations whose projects seem to us to be relevant and in line with the values of the Marathon:

Logos crea Mont Blanc et Sylvacct

We welcome any suggestions you may have concerning this issue.

The Aiguilles Rouges nature reserve

On the 23 km

On your way from Montroc to La Flégère, you'll pass through a small part of the nature reserve, where the fir trees provide some shade, before leaving the Bois de la Trappe.

On the 42 km

Follow part of the botanical trail at the top of the Col des Montets to Trélechamp. Small signs indicate the names of the most remarkable flowers that thrive here. At the top of the pass, behind the chalet, several ibexes have taken up residence (perhaps you'll catch a glimpse of them).
From Le Chaleyre, go up to the aiguillette des Posettes and cross the reserve (a marker indicates this). This area is home to chamois and wild boar. There is also an eagle nesting area at "les ardoisières". Don't look up, but look at your feet!

Coureur devant une chaîne de montagne enneigée
Chamois dans la nature
marmotte sur un rocher