Tour du Mont Blanc
Tour du Mont Blanc (TMB) is a classic long-distance loop around the Mont Blanc massif, running through France, Italy, and Switzerland and returning to the starting area. The commonly followed “classic” circuit is about 165–170 km with roughly 10,600 m of total ascent/descent, making it a big multi-day commitment rather than a typical point-to-point hike.
Most hikers plan on 9–14 days for a full circuit (with the loop’s usual walking direction being counter-clockwise). It’s designed as a hut-and-village route: you pass through multiple high valleys around the massif, with overnight options spaced so you can break the loop into segments.
The route typically uses a small set of major trailheads: Les Houches or Les Contamines in the Chamonix/Montjoie side of France, Courmayeur from the Italian side, and either Champex or near Martigny in Switzerland. The “official” line has changed over the years, and there are also variantes that reroute onto different cols or adjust the balance of difficulty and terrain.
One reason the TMB is so popular is that it follows mountain paths that are strenuous but not technically a scrambling route; instead, the work is cumulative—days of sustained climbing to passes/cols and then descending to the next overnight. Along the way, the trail system threads through seven valleys around the massif (Chamonix/Arve, Montjoie, Vallée des Glaciers, Italian Val Veni, Val Ferret, Swiss Val Ferret, and either the Arpette or Trient valley depending on route choice).
The highest points on common variants include Col des Fours in France and the Fenêtre d’Arpette in Switzerland, both around 2,665 m. The loop also has a recognizable shared section with the European long-distance footpath GR5 for part of the way between the Brevent summit area and the Col de la Croix du Bonhomme.
Lodging logistics are central to planning. Accommodation is plentiful across the full loop in the form of mountain refuges and valley towns, but the route’s popularity can create bottlenecks on peak dates—so booking strategy matters if you want specific hut beds or refuge overnights.
In summer, typical hiking season runs from late June to early September, when high passes are usually free of snow; weather in the Mont Blanc area can change rapidly, and conditions at high elevation can force timetable changes even mid-season.
More information: Wikipedia, The ultimate guide to solo hiking & camping the Tour du Mont ..., The Beginner's Guide to Trekking the Tour du Mont Blanc