Grotte de la Draye Blanche

Grotte de la Draye Blanche sits in the commune of La Chapelle-en-Vercors, in the Drôme department, tucked into the limestone heart of the Vercors massif. The cave forms a single vast chamber roughly 100 by 30 metres, connected to close to 400 metres of passages, all carved out long ago by underground rivers and lakes that once ran through the mountain. These days the site trades under the name Grotte de la Percée Blanche, though locals and older maps still refer to it by its original name, Draye Blanche.

How old is the cave?

Geologists put the cave's age at more than 4 million years, making it one of the oldest known karst formations in the Vercors. The scale of its stalactites, stalagmites, and columns backs that up — some of these formations have been building for thousands of years. What strikes most visitors, though, is the colour: the mineral deposits shift from bright white to rust and ochre tones, a record of how the water chemistry seeping through the rock changed over long stretches of time.

Who found it, and how?

The discovery goes back to 1918, and it started with a missing dog. Fabien Rey, a local trapper known around the area by the nickname "Marseille," lost his dog Fleury down a natural sinkhole (a scialet, in the local term for this kind of karst shaft). Rey lowered himself down on a rope to find the animal and stumbled onto a sprawling cave system instead. The cave was first named after the dog — grotte Fleury — before becoming Draye Blanche, and later Percée Blanche, the name it carries today. The proper entrance tunnel that visitors now walk through wasn't cut until 1990.

What has been found inside?

While workers were boring the new entrance passage, they broke into a natural shaft that had been sealed at the surface for millennia, acting as a trap for wildlife that fell in over the ages. Excavation of that shaft turned up around 15,000 bones representing 45 different species, ranging from shrews to cave bears. It's one of the richer paleontological finds in this part of the Vercors and gives a real sense of how varied the local fauna once was.

What should you know before visiting?

Access is guided only — no self-guided wandering — with groups capped at around 40 people. Inside, the temperature holds steady at about 11°C all year, so bring a layer no matter the season outside. A typical visit runs about an hour, with commentary offered in both French and English, including audio guides. On site you'll find parking, a small restaurant, a gift shop, and a picnic area, plus a seasonal animal park right next to the cave entrance.

Frequently asked questions

Where exactly is Grotte de la Draye Blanche located? In the commune of La Chapelle-en-Vercors, on the road toward Vassieux-en-Vercors, in the Drôme section of the Vercors massif.

How old is the cave? Estimates put its formation at over 4 million years ago, though the visible stalactites and stalagmites are far younger, having grown over thousands of years.

Can you visit without a guide? No — visits are guided only, and English-language tours are available alongside French ones.

What's the temperature like inside? A constant 11°C year-round, regardless of the weather outside.

What was discovered during the excavation work? Roughly 15,000 animal bones from 45 species, pulled from a natural shaft that had trapped wildlife over a very long span of time.

Is there anything else to do nearby? Yes — there's a restaurant on site and an adjoining animal park, making it an easy place to spend a few extra hours while exploring the Vercors.