Grotte des Planches

Grotte des Planches is a karst cave in the commune of Les Planches-près-Arbois, in the Jura department of eastern France, about 5 km from the town of Arbois. Its entrance opens onto the reculée des Planches, a typical Jura landform: a steep-walled, dead-end limestone valley that, together with the surrounding woods and meadows, forms part of a protected Natura 2000 site.

How did the cave and its waterfall form?

The cave was carved out of a limestone plateau through a classic karst process: rainwater seeps into the rock, hollows out a network of passages, and eventually resurfaces at the foot of the valley. That resurgence feeds the Cuisance river, which rises here from two linked springs, known locally as the small and the large Cuisance. Because the water carries a heavy load of dissolved limestone, it deposits tufa as it emerges, building up the tufa cascade that marks the cave's outflow and ranks among the site's best-known features.

How large is the cave, and who first explored it?

The passage network of the Grotte des Planches runs to nearly 8 kilometres, making it one of the more extensive cave systems in the Jura. It was first noted in 1813, though systematic exploration only began from 1904 onward, carried out in part by the geologist Maurice Piroutet. The cave was later fitted out for visitors and opened to the public in 1936.

What has archaeology found inside?

Excavations beneath the entrance porch and in a nearby gallery have uncovered successive layers of human occupation. Digs carried out over the years, including a campaign in 1975-1976 focused on the entrance porch, revealed traces of settlement spanning from the Upper Palaeolithic through to the late Bronze Age, buried at different depths beneath the present ground surface. That long sequence makes the cave one of the more informative prehistoric sites in the Jura region.

Can visitors still go inside today?

The cave itself has been closed to the public since 2011, after a dispute between the local council and the landowner over securing the access path, part of which had been buried by rockfalls, with further collapses still a risk. A project to reopen and refurbish the site was announced in 2022, so anyone planning a visit should check current status with the Arbois tourist office beforehand. The reculée des Planches itself, including views of the resurgence and the tufa cascade, remains open to walkers and is a popular destination for a short hike in the area.

FAQ

Where exactly is the Grotte des Planches? In the commune of Les Planches-près-Arbois, in the Jura department of eastern France, about 5 km from Arbois.

How long is the cave? Its passages total close to 8 kilometres, placing it among the larger cave systems in the Jura.

When was it explored, and by whom? It was first recorded in 1813, with systematic exploration starting in 1904, carried out in part by the geologist Maurice Piroutet.

Were prehistoric remains found in the cave? Yes — occupation layers spanning the Upper Palaeolithic to the late Bronze Age were uncovered mainly near the entrance porch, notably during excavations in 1975-1976.

Is the cave currently open to visitors? No — it has been closed since 2011 for safety reasons. A reopening project was announced in 2022, so it is worth checking current tourist information before planning a trip.