A north-south traverse of the Vercors, from the balconies above Grenoble to the Baronnies Provençales, via the great limestone wilderness of the Hauts-Plateaux.
185 km 115 mi12 stages7,400 m 24,278 ft ascentHigh point 1,968 m 6,457 ftSaint-Nizier-du-Moucherotte → Brantes
From Saint-Nizier-du-Moucherotte to Brantes, over 185 km.
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Elevation profile: from 510 m to 1,965 m over 185.4 km.
The GR91 at a glance
The GR91 crosses the Vercors massif from north to south. It starts from Saint-Nizier-du-Moucherotte, in Isère, above Grenoble, and ends in Brantes, in the Vaucluse, after crossing the Drôme and part of the Hautes-Alpes. Its entire northern section lies within the Vercors Regional Nature Park.
The first stages follow long balcony paths; the trail crosses the 45th parallel near Les Ravières, shortly after the start. Then comes the heart of the journey, the Hauts-Plateaux du Vercors: more than 17,000 hectares with no roads or permanent dwellings, protected by a national nature reserve, with the Grand Veymont (2,341 m), the highest point of the massif, and Mont Aiguille as a backdrop.
In the south, the landscape changes: the trail descends towards the Diois and then reaches the Baronnies Provençales, limestone mid-mountains with a Mediterranean feel, between the Diois and the Ventoux, as far as Brantes.
Beyond the physical effort, the main challenge of the GR91 is crossing the Hauts-Plateaux, which calls for real self-sufficiency: no villages, little water and nights in huts or in a tent. It suits well-organized hikers, able to carry several days’ food and manage their water. Variants and shorter sections, for example as far as Châtillon-en-Diois, let you discover part of it.
Highlights
Crossing the Hauts-Plateaux du Vercors, more than 17,000 hectares with no roads or permanent dwellings.
The views of the Grand Veymont and Mont Aiguille.
A complete change of scenery, from the balconies of the northern Vercors to the Baronnies Provençales and their Mediterranean feel.
Nights in unstaffed shelter huts, open to all, in the heart of the nature reserve.
A starting point you can reach by coach from Grenoble.
Practical information
Start
Saint-Nizier-du-Moucherotte
Saint-Nizier-du-Moucherotte is served from Grenoble by the T65 coach line of the Cars Région Isère network, which continues to Lans-en-Vercors. Grenoble SNCF station connects with the line.
Finish
Brantes
Brantes, a small village in the Vaucluse north of Mont Ventoux, has no railway station: plan your return in advance, by regional coach or taxi. Mon GR refers to the TER Auvergne-Rhône-Alpes and Provence-Alpes-Côte d’Azur websites.
When to go
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In May, snow can still get in the way above 1,400 m, especially on the Hauts-Plateaux. From mid-July to mid-August, accommodation is harder to find; according to Mon GR, October, and sometimes until mid-November, is when the weather is most reliably sunny.
Difficulty
Challenging
The difficulty lies mainly in the remote stages on the Hauts-Plateaux, with no villages or supplies and few springs, which demand a high degree of self-sufficiency.
Accommodation
2 refuges, 3 gîtes, 12 unstaffed huts, and 5 B&Bs
Gîtes, hotels, B&Bs, campgrounds and refuges line the route outside the Hauts-Plateaux. On the plateaux, the reserve’s shelter huts are unstaffed and open to all; you need to be self-sufficient there and respect the premises. Book your accommodation, especially between mid-July and mid-August.
Rules to know
In the Hauts-Plateaux du Vercors National Nature Reserve, dogs are banned, even on a leash. Bivouacking is allowed there from 5 pm to 9 am, for a single night, with a tent pitched in the evening and taken down in the morning. Fires are forbidden, except in the huts’ stoves, as are picking plants, leaving litter and flying drones; camping stoves are allowed.
Water and supplies
Springs are rare along the whole route, from the Vercors to the Baronnies. On the Hauts-Plateaux, an “Infos source” bulletin is published in summer on the Vercors Regional Nature Park website, but it is not daily, the flow from the springs varies and the water quality is not tested. The water points built in the summer pastures (rainwater catchments) are reserved for livestock.
The GR91 on the map
The 12 stages
TrekGR stage plan: each stage ends where you can sleep. Actual walking time excluding breaks (DIN 33466 standard).
No current alerts for this GR (checked on November 12, 2026). All live updates →
Our advice
Check the Vercors Park’s “Infos source” bulletin before entering the Hauts-Plateaux and carry something to treat water.
Carry food for the whole crossing of the Hauts-Plateaux, where there are no supplies at all.
Bring bivouac gear, even if you plan to sleep in the shelter huts.
Leave your dog at home: it is banned in the nature reserve, even on a leash.
Book gîtes and hotels in advance if you are walking between mid-July and mid-August.
Take all your trash away with you, including toilet paper and glass bottles.
Frequently asked questions
Where does the GR91 start and finish?
The GR91 starts from Saint-Nizier-du-Moucherotte, above Grenoble, and finishes in Brantes, in the Vaucluse. It crosses the Vercors from north to south, then the Diois and the Baronnies Provençales.
Is there water on the Hauts-Plateaux du Vercors?
Very little. Springs are rare and their flow varies; the Vercors Park publishes an “Infos source” bulletin in summer, though not daily, and the water quality is not tested. Set off with enough water and something to treat it.
Can you bivouac on the GR91?
Yes. In the Hauts-Plateaux nature reserve, bivouacking is allowed from 5 pm to 9 am, for a single night; fires are forbidden there except in the huts’ stoves. The reserve’s welcome booklet sets out the rules.
Can you walk the GR91 with a dog?
Not all of it: dogs are banned in the Hauts-Plateaux du Vercors nature reserve, even on a leash, and the GR91 crosses it.
Do you need to book the huts on the Hauts-Plateaux?
The reserve’s shelter huts are unstaffed and open to all. It is wise to bring bivouac gear, and to leave the hut clean when you go.
What is the best season for the GR91?
From June to October. In May, snow can still get in the way on the Hauts-Plateaux; fall is often the sunniest period, and high summer the busiest for accommodation.
Route: OpenStreetMap contributors. Elevation: IGN’s RGE ALTI®, one point every 50 m. Text checked on November 10, 2026.
