Meulières du Mont Vouan, Historical quarry site in Viuz-en-Sallaz, France.

Meulières du Mont Vouan is a quarry site in the Alps where large, circular holes were blasted into the rock to produce millstones. The area spans seven distinct extraction zones with multiple levels and chambers that remain accessible today.

From the Early Middle Ages, millstones were extracted here for grain processing across the region. Systematic extraction ended in the late 19th century as new production methods replaced traditional stone quarrying.

The name Grand'Gueule, one of the excavated quarries, refers to the wide mouth of its opening. A local legend tells of a man finishing his millstone on Christmas Eve who slipped into the Gouille aux Morts pond at the foot of Mont Vouan and drowned in the mud; his body was never found. The quarries are signposted with panels on the history of the work, bread and daily life of the workers.

The site is reached via a marked hiking trail of around 6 kilometers starting from La Source qui Rit parking area, which leads upward to the quarries. Sturdy footwear and caution are needed as paths are uneven and some chambers have tight passages.

A single millstone once cost as much as a house, which made these quarries a gold mine for Faucigny residents. The 2010–2011 survey by Grenoble University and CNRS historians and archaeologists, first by plane then on foot, climbing the cliffs, found 72 millstone quarries, making Mont Vouan the largest millstone site in south-eastern France.