Mont Blanc is the highest mountain in the Alps and in western Europe, on the border between France and Italy, and its height is usually given as about 4,808 metres — a figure that changes slightly every year. Its first ascent in 1786 is generally taken as the birth of mountaineering as a pursuit rather than an occupation.
Three countries around one massif
The Mont Blanc massif sits at the junction of France, Italy and Switzerland, and each has a valley beneath it — Chamonix, Courmayeur and, a little further off, the Swiss Val Ferret.
The Tour du Mont Blanc, a walking circuit of roughly 170 km around the massif crossing all three countries, is among the most walked long-distance routes in the world. It is a useful reminder that the great majority of people who come here never go above the treeline, and that the massif's economy rests on walkers and skiers rather than on the several thousand who attempt the summit.
The height that will not stay still
Most mountains have a fixed published height. Mont Blanc does not, because its summit is not rock but a dome of ice and compacted snow lying over the rock beneath.
The thickness of that cap varies with snowfall and wind, so the measured summit elevation moves — surveys since the 2000s have recorded values ranging roughly between 4,805 and 4,810 metres. French surveyors remeasure it every two years, and the announcement of the new figure is a minor national news event.
The rock summit beneath is somewhere around 4,792 metres. Which number counts as the mountain's height is a question of convention: for Mont Blanc the ice is included, as it is for most glaciated summits.
Whose summit is it?
The border between France and Italy in the Mont Blanc massif has never been entirely settled, and the summit itself is disputed in a low-key way that neither government presses.
The French position, deriving from a nineteenth-century interpretation, places the summit within France. The Italian position, based on the 1861 treaty and the principle that the border follows the watershed, places it on the frontier so that the peak is shared. Maps published in the two countries differ accordingly, and have for over a century.
Nothing turns on it practically — there is no infrastructure, no resource and no population — which is precisely why it has never been resolved. It is one of the more genteel border disagreements in Europe, conducted entirely through cartography.
1786, and the invention of a pastime
In 1760 the Genevan scientist Horace-Bénédict de Saussure offered a reward to anyone who found a route to the summit, motivated by an interest in barometric measurement and natural philosophy. It stood unclaimed for 26 years.
On 8 August 1786, Jacques Balmat, a local crystal hunter, and Michel-Gabriel Paccard, a Chamonix doctor, reached the top. Saussure himself climbed it the following year with a large party.
The significance is that before this, mountains were obstacles, sources of hazard, or places of work — nobody climbed them for the sake of it. The Mont Blanc ascent, driven by scientific curiosity and a cash prize, established the idea that a summit could be an objective in itself, and Chamonix became the first place in the world organised around that idea. The Compagnie des Guides de Chamonix, founded in 1821, is the oldest guiding organisation anywhere.
The credit was disputed almost immediately, with Balmat claiming primacy and Paccard's contribution downplayed for a century before later scholarship restored it — an early instance of the summit-claim controversies that have followed mountaineering ever since.
The normal route, and how many people use it
The Goûter route from Saint-Gervais is the usual line: a lift and rack railway to the Nid d'Aigle, then a climb to the Goûter hut at 3,835 metres, and a long snow ascent over the Dôme du Goûter and the Bosses ridge to the summit.
Something like 20,000 people attempt it each year, which is an extraordinary number for a 4,800-metre glaciated peak. The route is not technically hard, but it involves crevasse hazard, altitude, and the Grand Couloir — a gully crossed on the way to the Goûter hut that is swept by rockfall and has killed a large number of people over the years.
Crowding has become a management problem. The Goûter hut has limited beds, unregulated parties have bivouacked on the mountain, and local authorities have at various points imposed permit requirements, restricted numbers, and introduced fines for climbers arriving without a hut reservation. The mayor of Saint-Gervais has publicly proposed a deposit to cover rescue and body-recovery costs.
The tunnel, and the fire
The Mont Blanc Tunnel, opened in 1965, runs 11.6 km beneath the massif between Chamonix and Courmayeur, and it transformed freight movement between France and Italy by removing a long detour.
On 24 March 1999 a lorry carrying flour and margarine caught fire inside it. The fire burned for two days at temperatures reported above 1,000 degrees Celsius, and 39 people died, many trapped in vehicles behind the blaze. The disaster led to a fundamental reassessment of tunnel safety across Europe — ventilation, refuges, emergency access, and restrictions on heavy goods traffic — and the tunnel remained closed for three years.
The event is a reminder that the massif's most consequential infrastructure is not on the mountain but through it, and that its risks are industrial as much as alpine.
The massif, and a laboratory for alpinism
Mont Blanc heads a massif containing some of the most celebrated climbing terrain in the world: the granite spires of the Aiguilles above Chamonix, the Grandes Jorasses with its formidable north face, the Aiguille du Dru, and the Mer de Glace, the longest glacier in France.
Chamonix is consequently the historic centre of technical alpinism, and successive generations have used the massif to define what was possible — the north faces in the 1930s, the hard granite routes of the post-war decades, and the extreme skiing and speed ascents of recent years.
The glaciers are in visible retreat. The Mer de Glace has thinned dramatically, and the staircase built to reach it from the Montenvers railway has been extended repeatedly as the ice surface has dropped — each extension marked with the year, so the descent to the glacier is now a physical timeline of ice loss. Permafrost thaw in the high rock is increasing rockfall, closing routes that were climbed for a century.
The cable car that changed everything
The Aiguille du Midi cable car, completed in 1955, rises from Chamonix at 1,035 metres to 3,842 metres in two stages — for decades the highest cable car in the world, and still among the most dramatic.
Its effect on climbing was profound. Routes that had required a full day's approach and a night in a hut became accessible in a morning, and the high mountain opened to people with limited time. The Vallée Blanche descent from the top station — a long off-piste ski run down the Mer de Glace glacier system — became one of the most famous ski itineraries anywhere, done by thousands who would never otherwise be on a glacier.
That accessibility has a cost. The arête leading from the top station onto the glacier is a genuinely serious piece of ground, and people step onto it every season without the equipment or knowledge to be there. Mountain rescue in the Chamonix valley — run by the PGHM, a specialist gendarmerie unit — is among the busiest in the world.
Skiing, flying and the rest of the massif's uses
Mont Blanc has become a laboratory for extreme mountain sport as much as for classical climbing. Steep skiing developed here, with descents of couloirs on the Aiguilles that were considered unskiable; paragliding from the high lifts is routine; and speed records on the standard route are contested regularly.
The Ultra-Trail du Mont-Blanc, a running race of some 170 km circling the massif through France, Italy and Switzerland with over 10,000 metres of ascent, has become one of the defining events of trail running and brings very large numbers of people to the valley each August.
All of it rests on the same accident of geography: a very high massif with deep valleys and road access on three sides, in a wealthy part of Europe, with a two-century head start on infrastructure.
Against the Matterhorn, and against Elbrus
Mont Blanc sits in two comparisons that come up constantly:
- Against the Matterhorn: Mont Blanc is higher and its ascent is longer and less technical; the Matterhorn is more famous and more photogenic, and its history is one of scandal rather than of foundation.
- Against Elbrus: whether Mont Blanc is Europe's highest mountain depends on where the continental boundary falls in the Caucasus. Under the watershed convention Elbrus wins at 5,642 metres; under the Kuma–Manych convention Mont Blanc does.
What is not in dispute is precedence: whatever the ranking, the sport of climbing mountains started here in 1786, and everything from the Matterhorn to Everest follows from it.