Heritage Days 2025, the program at Château de Beaumont-sur-Oise (95)

Are you ready to rediscover Paris Region's superb heritage during the 41st Journées du Patrimoine? Across the Île-de-France region, explore castles, historic monuments, museums and other exceptional sites, and learn from enthusiasts. Take advantage of free events and guided tours, particularly in Val-d'Oise, where the Château de Beaumont-sur-Oise, a vestige of the Middle Ages, awaits you from September 20 to 21, 2025.

But before you visit, let's take a look at the castle's history: the 7th century marked the first turning point in the evolution of this Val-d'Oise building. It was at this time that construction began on its great stone keep (37 m high). Higher than the bell tower ofSaint-Laurent church (32 m), it was used to store food on the first floor, and to house the lord's apartments upstairs. In 1223, the last Count of Beaumont died without issue, and the castle was bought by King Louis VIII, thus becoming part of the royal domain.

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In 1226, Louis IX, the future Saint Louis, took up residence at the château and had the Royaumont Abbey built. During the 14th and 15th centuries, the château underwent numerous assaults, destructions and reconstructions: the Hundred Years' War, sieges by the English, French, Burgundians and Armagnacs. The castle and town were occupied by the English between 1420 and 1435. The last major transformation of the château took place in the 18th century.

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With the advent of artillery, weapons became increasingly powerful, and the castle's defensive structure had to be reinforced. The height of the keep was reduced from 37 meters to around 5 meters. The castle became an artillery stronghold. The château then lost its grandeur and was abandoned in 1815.

Journées du Patrimoine 2025: the program for the most beautiful châteaux in Paris and the Île-de-France region
The Journées du Patrimoine 2025 is also an opportunity to visit castles in the Paris region, often free of charge! Kings and queens, princes, emperors, nobles of all kinds... Follow in the footsteps of these great figures of French history and discover their magnificent homes, on September 20 and 21, 2025. [Read more]

The 2025 Heritage Days program at Château de Beaumont-sur-Oise (95)