Grottes de Cliersou

Grottes de Cliersou are man-made caves cut into the flank of Puy de Cliersou (also spelled Clierzou or Clersioux), a volcanic peak in the commune of Orcines, in the Puy-de-Dôme department of France's Auvergne-Rhône-Alpes region. The site sits within the Chaîne des Puys, a UNESCO World Heritage volcanic chain, a short drive from Clermont-Ferrand and right next to the far better-known Puy de Dôme.

Where exactly are the caves located?

Puy de Cliersou is a trachyte lava dome, one of the younger volcanoes in the Chaîne des Puys, formed roughly 11,000 years ago. Its summit reaches 1,199 metres. The caves are carved into its slope, surrounded by the heathland, meadows and beech-fir woodland typical of this stretch of the Auvergne volcanic chain.

How did the caves come to exist?

Unlike most caves, Grottes de Cliersou are not a product of natural erosion — they were dug out by people. Quarrying of the trachyte rock began under Gallo-Roman rule in the 2nd century AD and continued into the Merovingian period. The stone served two purposes: some blocks were shaped for construction and used in the Temple of Mercury built on the summit of Puy de Dôme, while others were carved into sarcophagi. On several cave walls, the recessed, coffin-shaped outlines left behind by that sarcophagus-cutting are still visible today.

What is there to see once you arrive?

The signature feature of the site is the cave opening itself, which frames a striking view of the Puy de Dôme cone — one of the most photographed vantage points in the whole Chaîne des Puys, particularly at sunrise and sunset when the light rakes across the volcanic landscape. From the summit of Puy de Cliersou, the panorama widens further to take in Puy Pariou, the Sancy massif, and the neighbouring domes of Puy de Côme and Puy de Fraisse.

How do you get there, and how long does the hike take?

Most visitors start from the Fontaine du Berger car park, from which a trail climbs to the summit of Puy de Cliersou and the cave entrances. The loop covers about 6.7 km, gains roughly 230 metres of elevation, and takes around two hours at a moderate pace. An alternative starting point is the Puy des Goules car park, offering a gentler, longer northern approach (about 3.8 km) or a steeper, shorter southern one (about 3.4 km); a longer combined route also links Puy Pariou with Cliersou for hikers wanting a fuller day out. Trails are waymarked and manageable for reasonably fit walkers, though sturdy footwear is worth having given the loose volcanic ground underfoot.

Frequently asked questions

Are the Grottes de Cliersou natural caves? No. They were excavated by hand from the trachyte rock, with quarrying dating back to the Gallo-Roman era.

What was the extracted stone used for? Some blocks were shaped into building material for the Temple of Mercury atop Puy de Dôme; others were carved into sarcophagi, whose outlines remain visible on the cave walls.

How long does the walk to the caves take? The loop from the Fontaine du Berger car park takes about two hours and covers just under 7 km.

Is the trail suitable for families? The elevation gain is moderate — around 230 metres — so it's manageable for older children in reasonable shape, though the volcanic terrain can be uneven in places.

What else can be combined with a visit to the caves? Because the trailheads are shared with routes up Puy de Dôme and Puy Pariou, many visitors extend their outing into a longer hike across this section of the Chaîne des Puys.