The Château Mont-Royal is a French castle in La Chapelle-en-Serval, Oise, built for Fernand Halphen by the architect Guillaume Tronchet, and currently used as the Chateau Hotel Mont Royal.

After having rejected the project with the Anglo-Norman style of the architect René Sergent, then the first project of a mediaeval style of the architect Guillaume Tronchet (drawings in the Musée d'Orsay), Halphen chose Tronchet's second plan, of a castle celebrating hunting on the outside and music on the inside.

Constructed from 1907 to 1911, the castle (transformed into a hotel by Jean Pierre Hermier in 1989)[1] was a great architectural success.

In 1989, J.P. Hermier bought it from the descendants of Fernand Halphen and had it transformed into a hotel, which opened its doors in 1990.

The hotel has one hundred and nine rooms including five suites, a restaurant and an indoor swimming pool.