Heritage Days 2026 at Montgeroult Castle: an exceptional opening on the agenda

Every autumn, Île-de-France reveals its best-kept historical secrets. For Heritage Days 2026, head to Val-d'Oise to swing open the gates of Montgeroult Castle, an architectural treasure that is exceptionally opening its doors to the public.

Behind this imposing wrought-iron gate lies one of the best-kept secrets of the Île-de-France countryside. Each year, the Heritage Days 2026 open up spaces normally off-limits, from private residences to the back rooms of our most stunning monuments in Paris and the Île-de-France region. For this new edition, taking place on the September 19 and 20, 2026, head to the Val-d'Oise to discover the Château de Montgeroult, a property that rarely unveils itself to curious visitors.

Built in the 17th century and later redesigned in the following century, the estate masterfully embodies classical French architecture. This architectural current is defined above all by a pursuit of symmetry, noble proportions, clean lines, and restrained decoration, highlighting the pale limestone typical of the Vexin.

The site centers on a manor house surrounded by well-kept outbuildings, all set in a tree-lined park that overlooks the Viosne valley. Local lore has it that the estate hosted lively intellectual salons and counted among its visitors prominent figures of the Enlightenment, even if archival records offer only faint traces of such regular gatherings.

Today, this private residence listed as a historic monument is devoted to sharing the art of noble living from bygone days and to preserving a discreet slice of Île-de-France's history. Here is the detailed program crafted for this exceptional weekend opening.

Heritage Days 2026 program at Montgeroult Castle in Val-d'Oise

Tour of the grounds, the Orangery, and the park at Montgeroult Castle
Self-guided tour of the château’s exterior grounds, the orangery, and the park
Participation requirements: Free admission – Free | No reservations required
Hours: Saturday, September 19, 2026 — 2:00 PM to 6:00 PM | Sunday, September 20, 2026 — 2:00 PM to 6:00 PM
Inside Montgeroult Castle: a guided tour of its interiors
Guided tour of the drawing rooms at Montgeroult Castle
Participation conditions: Price: €8 per person, free for those under 18. Limited to 25 people per tour. - Special rate | No reservation required
Schedule: Saturday, September 19, 2026 — 2:30 PM–3:30 PM | Sunday, September 20, 2026 — 4:30 PM–5:30 PM

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