23km: an historic race

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23km
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Logo 23km du Mont-Blanc

23km du Mont-Blanc

Created in 1979, the Cross du Mont-Blanc will celebrate its 46th edition in 2025. This popular race, whose route has barely changed since its creation, will take you in the tracks of the discipline's pioneers, surrounded by a breathtakingly beautiful panorama!

To take part in this race, it is recommended to have good mountain running experience, to be comfortable on all types of terrain and to be self-sufficient for several hours. Please note that a runner with an UTMB index inferior to 270 points has very little chance to finish the race, so it is recommended to register for another Mont-Blanc Marathon race.

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Départ 23km 2024
Logo Marathon du Mont-Blanc

Race info

23km semi-autonomous trail run

1680m D+ / 870m D-

Open to Espoirs and above

Limited to 2,000 runners

6 starting waves

Maximum time: 6 hours

2 full feed stations + 1 finish feed station

Interactive map PDF map Estimated passage times Race profile

Bibs pick-up

Bibs pick-up for the 23km will be possible by appointment only, at the EMC2 space on Place du Mont-Blanc (Chamonix):

  • Thursday June 26, 2025 from 9am to 9pm,
  • Friday June 27, 2025 from 9am to 9pm.

Runners must present photo ID and a race bag containing all compulsory equipment, to enable a timing chip to be fitted and equipment to be checked.

No bibs will be issued to runners without their compulsory equipment and identity papers. No bibs will be distributed on the Saturday morning before the start of the race.

Compulsory equipment

  • Cell phone in working order.
  • Minimum 0.50-liter water supply.
  • Waterproof jacket with hood (gore-tex type) adapted to your size.
  • Survival blanket (140cm x 200cm).
  • Tumbler.
  • Whistle.
  • Cash.

Recommended equipment

  • Cap.
  • Tights.
  • Gloves.

Time barriers

The time limits given below can be modified in the case of bad weather conditions and for safety reasons ; the organization reserves the right to stop the event in progress or modify the time limits. All decisions will be taken by the race jury.

  1. Montroc feed station (km 12): start time of last wave + 2h30.
  2. La Flégère feed station (km 18): start time for last wave + 4.30 hrs.
  3. Maximum race time - Chamonix Planpraz (23km) : Start time for each wave + 6h.

A runner arriving at a time barrier point, after the time barrier has been applied, will be disqualified. The lower right-hand corner of the race number will be "cut out" by the station manager and the runner will be invited to return to Chamonix. Should the runner wish to continue on the course, his or her number will be collected by the station chief and the runner will no longer be considered a participant in the Mont Blanc 90km, and will therefore no longer be under the responsibility of the organizer. Anyone disrespecting the volunteers responsible for enforcing the time limits will be banned from all Mont Blanc Marathon events.

Maximum race time

Runners crossing the finish line after the maximum race time will not be classified and therefore not considered as finishers. This maximum time is calculated according to the start time of your wave.

23km du Mont-Blanc: maximum race time 6h00

 

The organizers would like to draw runners' attention to the fact that, depending on the systems and settings used, GPX tracks may give different results for race distances and gradients.

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Départ 23km 2024
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23km
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23km 2024
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23km

Relive past editions of the 23km du Mont-Blanc