Grotte des Faux-monnayeurs

Grotte des Faux-Monnayeurs (Cave of the Counterfeiters) is one of the most intriguing underground sites in the Franche-Comté region, opening in a limestone cliff above the Loue and Lison valleys, in the commune of Mouthier-Haute-Pierre, department of Doubs. It brings together three layers of history: traces of settlement going back thousands of years, a legend about a band of fugitive coin forgers, and a present-day role as a favorite destination for caving and climbing.

Where exactly is the cave located?

The entrance opens in a rock wall overlooking the area of the Gorges de Nouailles and the Source du Lison, close to the Loue valley. The portico is roughly 7 meters high and 5 to 6 meters wide, set about ten meters above the valley floor; a ladder fitted with a handrail gives access to it. Underground, the cave connects to the neighboring Grotte de la Vieille Roche and to the Pontet spring, forming a single karst system.

Why is it called the Cave of the Counterfeiters?

The name is tied to archaeological finds: Gallic coins, along with coins from later periods, were unearthed here together with pottery, fibulae and axes. Local tradition adds a story on top of these finds — the cave is said to have sheltered a gang of coin counterfeiters who hid there during a period of armed unrest in the region. Accounts differ on exactly when this took place, so the counterfeiter story is best treated as local folklore rather than an established historical fact, unlike the coin finds, which are archaeologically documented.

What has been found inside the cave?

The Grotte des Faux-Monnayeurs ranks among the most important archaeological sites in the Doubs department and in the Bourgogne-Franche-Comté region as a whole. The earliest traces of human presence date to the Neolithic, between roughly 6000 and 2500 BC. Excavations carried out in the 1960s uncovered metal objects — knives, pins, bracelets — suggesting that a few families once lived inside the cave, sustaining themselves through farming and livestock. The cave itself extends for about 1,295 meters, with a vertical relief of 55 meters. The interior is spacious and largely dry (fossil), which allows visits year-round without weather-related risk — except during floods, when underground water surges back out through the entrance in dramatic cascades.

How do you get there, and how long does a visit take?

The starting point is the car park at the end of the Guenbards path in Mouthier-Haute-Pierre. Reaching the entrance takes about 20 minutes on foot and does not require advanced fitness. Exploring the interior, whether on a simple guided walk or an introductory caving trip, calls for a headlamp and sturdy footwear. The site is also known among climbers: a dozen or so routes of varying difficulty have been bolted into the rock above the entrance, and some of them actually begin with a short underground scramble through the cave itself.

Is it suitable for children and beginners?

Thanks to its relatively easy approach and roomy passages, the Cave of the Counterfeiters is a popular choice for a first caving experience, open to children from around age 8 when accompanied by a guide. Local outdoor operators run half-day discovery outings here that combine natural and historical interest with genuine underground activity.

Frequently asked questions

Can you visit the cave on your own? Physical access is possible, but because of the ladder at the entrance and the total darkness inside, a guided outing is recommended, especially for a first visit.

Is the cave safe to visit after rain? During heavy rainfall and floods, part of the system fills with water that surges back out of the entrance as a waterfall; visiting the interior is not advisable under those conditions.

What did archaeologists find during excavations? Gallic and later coins, pottery, fibulae, axes and everyday metal objects, pointing to a long but discontinuous history of human presence inside the cave.

Does the cave connect to other caves nearby? Yes — underground, the system links to the Grotte de la Vieille Roche and to the Pontet spring, all part of the karst network associated with the Loue and Lison valleys.