What if the Heritage Days 2026 offered a chance to follow the trail of a mill that lost its grinding stones but not its history? In Châteaufort, in the Yvelines, the Moulin d’Ors hides in the heart of the Mérantaise valley, within the Haute Vallée de Chevreuse Regional Natural Park. On September 19 and 20, 2026, the Heritage Days will spotlight these historic structures—whether famed or more intimate—thanks to a concept that fuels their appeal: inviting the public to discover heritage sites in a new light, some of which are only rarely opened to visitors.
The Ors Mill used to belong to the vast Ors Estate. Archives record a hydraulic mill dating back to the 17th century, but the building visible today dates from the first half of the 19th century. Powered by a diversion from the Mérantaise, it was mainly used to grind wheat flour.
Its silhouette deserves a closer look. Unlike the small rural mills that sit low, the Ors mill rises in three levels, following the model of the “English windmills”. Its rough-faced meulière façade, the half-moon openings, and the remnants of its large iron wheel make it a distinctive example among the dozens of former mills listed in the regional natural park. This originality notably earned it the “Regional Heritage” label.
The mill has adapted to the times. Owned by the municipality of Châteaufort, it was restored by the Regional Natural Park in 1995. It now houses part of the park’s technical teams and a meeting room used especially by local associations. Its preservation mainly serves to keep a tangible reminder of the place once occupied by mills and hydraulic power in the Chevreuse valley.
The Domaine d’Ors adds another dimension to this story: the former castle park has today become a protected natural area, where built heritage, the river, wet meadows and woodlands sit side by side. A nice reminder that Île-de-France's heritage goes beyond old stones.
Discovering the Mérantaise Mills
A guided walk along the Mérantaise from the Ors Mill to the Neuf Mill, via the Vassaux Mill, to uncover how these mills work and the role of millers in local life. A visit to the church of Villiers-le-Bâcle is scheduled at the end of the route, focusing on the plants used in the church’s decoration and their mystical symbolism.
Participation conditions: Limited to 30 people — Free | No reservation required
Schedule: Sunday, September 20, 2026 — 3:00 PM to 5:00 PM
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Dates and Opening Time
On September 20, 2026
Location
Ors Mill
moulin d'ors
78117 Chateaufort
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