The Marathon starts early in the morning at the Place du Triangle de l’Amitié. Limited to 2000 competitors, the runners line up to take on the challenge of running from Chamonix to Argentière to Plan Praz (the Brévent mid-station).
From the centre of Chamonix (1035m) the runners set off along the river Arve, passing through the hamlets of Les Bois and Lavancher. It is a steady climb for about 15km until they reach Argentière at 1250m. The route then crosses the Col des Montets (1461m) in the heart of the Aiguilles Rouges game park. Following the Chemin des Diligences, the old stage-coach route, the course arrives at the hamlet of Le Buet before reaching Vallorcine (1260m), a quiet village nestled at the bottom of the valley, just on the edge of the Swiss border.
The runners then climb up to the Col des Posettes at 1997m where (if they can still see straight!) they can take in splendid views over the Mont Blanc massif, opposite the Aiguille and the Tour glacier. The route then gradually descends across the mountain passes to reach Charamillon at 1850m. A steady incline takes the runners up to the village of Le Tour (1453 m) before flattening out along the road leading to Montroc (1382 m).
After passing through the hamlets of Frasserands and Tré-le-Champ the route returns back onto the historic route of the Mont Blanc cross-country race. At the heart of the Aiguilles Rouges massif, opposite the Mont Blanc range, the route ascends until La Flégère (1875m) after crossing the magnificent Charlanon Coomb (1812m). A gentle yet progressively steeper climb makes up the final stretch, bringing the runners to the finish at Planpraz (2050 m), which offers further spectacular beautiful views of Mont Blanc.
The beginning of the race, from Chamonix to Lavancher is mostly in the shade of the trees. However, much of the race (especially the final stretch from La Flégère to Plan Praz) is under the full glare of the summer sun. This race is much more grueling than your average marathon; not only is much of it over cross country trails and up steep ascents but Chamonix itself is almost as high as Mount Snowdon – so before the runners even set off they are struggling with racing at high altitude! This is evident in the race times; the average Marathon du Mont Blanc winner usually completes the course in around 4 to 4 1/2 hours. If you compare this with the more well-known London and New York marathons, where the average winning time is usually just over 2 hours, you can see a clear difference.