Septmonts (French pronunciation: [semɔ̃]) is a commune in the Aisne department in Hauts-de-France in northern France.

The castle was the country seat of the Bishop of Soissons, probably since the last half of the 12th century and was first built in stone a little before 1242.

Thought to have been inspired by the works of Charles V of France, the 43 metre tall donjon, exemplifies the princely style of the late 14th century, combining both military and residential function.

The other sights at the chateau include: The village contains a fifteenth-century church in the flamboyant style.

This Soissons arrondissement geographical article is a stub.