La Jonction

La Jonction: One of the Chamonix Mega-Classics

Out and backs aren't always ideal, but in this case, you get twice the viewing time

→ 16km

↑ 1700m

Δ 2589M 

♦ Medium

Θ Out & Back

La Jonction is one of the Chamonix runs you send people to if they have limited time in the valley, want heaps of vertical, and hope to see the big mountains up close. As mountain runners, often times our goals are summits, but with La Jonction, the goal is the end of the trail, the edge of the glaciers. You are still far below the summit, feeling tiny, and standing in awe at the ice flowing from high on Mont Blanc.

La Jonction is also a huge amount of vertical in a short distance that is commonly done as an out and back. The trail starts at 1000 meters in Les Bossons, and meets its end 8km higher, 1600 meters above at La Jonction. There, you’ll give your legs a rest on a rocky island splitting the massively wide glacier sweeping down Mont Blanc into the Glacier de Taconnaz and Glacier des Bossons.

You’ll start this tour with some time switching back and forth in the forest before trees thin to bushes and you start to get glimpses of what you are surrounded by, which is mostly ice. 

Finally, you reach the alpine world where just below the top you scramble up some rock and pull on a few cables before the last bit of talus to the flat finish. The last bit of dry ground is flat where rock meets ice, gaping crevasses and some seracs. 

Take a dry shirt, something warm to slip on, and a snack to enjoy as you sit stunned by the landscape. 

Don't forget to peer over to the Grand Balcon Nord, just north from La Jonction beneath the Aiguille du Midi.

Detailed GPX Track

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GPX Track
Start:   45.900032, 6.840509
Town:  Chamonix
Department:  Haute-Savoie
Country:  France

  • There is a small hut about half way up the route, the Chalet des Pyramides, where you can typically get food and drinks. 

  • Have extra food & drink for a good long sit at La Jonction.

  • While it is a great trail, this route really is all about what you'll see, save it for the right conditions.

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Trail running in Chamonix, France

A lower angled section of the route alongside the Glacier des Bossons


Looking, and feeling, pretty alpine on a snowy fall day with the Aiguille du Midi and Glacier des Bossons above.


Nearing the end of the up at La Jonction, the trail is about to abruptly end at a massive glacier.


Arriving at La Jonction, you've run out of dry ground.


At La Jonction, you've gained 1700 meters but there is still over 2000 meters of mountain above.

Comments 3

  1. I used this site for all my routes for a 4-day running trip to Chamonix. Hands down the best mountain running resource for the Alps on the internet. Hats off to Kim and Dan.

    I did this route on day 1. A mega classic that more than lived up to the hype. Great way for the legs to get friendly with Chamonix vert. Those views.

    Bonus: I actually met Kim and Dan on the trail. Nice to meet you both!

    1. Ryan, this is so nice of you and very much appreciated! What you said about all the shit content online is what prompted us to do this. We’re stoked to be shit free! We are very grateful to have met you on the Jonction Trail, thanks for stopping to say hi!

  2. First of all — huge thank you to Dan and Kim, this blog is hands down the best trail running resource on the internet. I spent a week in Chamonix from October 8th – 14th and used the Chamonix guide to inform all my runs.

    Date Ran: October 12, 2023
    Conditions: 16 degrees celsius, colder in the morning before sun comes out and cold at the top with the wind blowing off glacier. I lucked out with the weather in early october… 7 days of moderate temps and sun every day made for gorgeous conditions. But was told that is atypical and can be much colder + some rain.

    Notes: Trail was in excellent shape, its one you can run very quickly and the descent is buttery smooth. The glacier is stunning up close. This run has it all and 100% lives up to the “mega classic” status! I jogged over to Le Bosson from town which was easy, just ~3km or so from Cham Sud each way. One last note: the train through town was closed for repairs from Oct 8th, was told it would reopen around end of Oct. They were running a bus from the train station in-line w scheduled train times and stops.

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