The Subterranean Limestone Quarries of Conflans-Sainte-Honorine

The abandoned underground limestone quarries of Conflans-Sainte-Honorine (All images by; Val-d’Oise’s stunning limestone quarries)

Hidden away beneath the picturesque landscape of Val-d’Oise, in the Île-de-France region, lies a network of subterranean limestone quarries that are spectacular to behold. The abandoned underground galleries, which are situated between the quiet communes of Herblay and Conflans-Sainte-Honorine, date back centuries and showcase a rugged industrial architecture that’s as functional as it is breathtaking.

Limestone pillars support the roof in one of Val-d'Oise's forgotten underground quarries

Vernacular arches give way to vaulted tunnels that connect different quarry locations. In some areas, the roof is supported by great limestone pillars that wouldn’t look out of place on the Star Wars set. A date carved into a keystone bears the inscription “1762”, attesting to the longevity of these long-abandoned yet hauntingly-preserved underground quarries.

Underground quarrying in France

But as with many constructions of old, their architectural grandeur was born of necessity. The subterranean quarries near Conflans-Sainte-Honorine lie close to the banks of the Seine river, which required a shallow dig to avoid flooding. As a result, the arches and pillars were built to support the more crumbly sub-surface rock and soil above.

Photographer Pierre-Henry Muller first visited the location in October 2006. He wrote on his website that two large parallel galleries had been constructed long ago in a bid to exploit the area’s extensive supply of limestone. He added that the smaller galleries had been constructed between the main ones to help ventilation and air circulation, as well as to provide miners with easy access to different quarries within the network.

Writing on his website, Muller said: “The most impressive achievement remains the arches made at the intersection of two galleries, The keystones bear the date 1762 and are an achievement unique in Europe and probably in the world. Moreover, it is very rare for the quarry workers to attach much importance and time to consolidating the excavated spaces, but the excessive fragility of the [roof] has pushed them to secure their place of work.”

Inscriptions on the wall inside the abandoned underground quarry (All images by

For more compelling examples of lost industrial architecture, check out our feature covering the abandoned mines, quarries and collieries of Britain.



Popular Posts


Latest Articles



Explore Urban Ghosts


Abandoned & Urbex


Send this to friend

Urban Ghosts uses cookies to enhance your browsing experience and to serve you with advertisements that might interest you. By continuing to use this site, you agree to our use of cookies. Privacy Policy

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.