Built around 1150 by Guy III le Bouteiller de Senlis, the castle dominates the county of Senlis, thanks to its formidable keep, probably the highest in the royal domain at the time of its construction (around 1190-1200). Testimony to a prestigious medieval past, the remains of the castle-fortress include, in addition to the keep, an enclosure with a polygonal ditch, an entrance châtelet (12th, 13th, 15th centuries) through which the bailey is accessed, a curtain wall with machicolation (14th century) linking the keep to the lord's dwelling and its semi-circular flanking tower (14th century). The castle and its seigneury have belonged to a succession of historical figures, each close to a king of France. Open to the public from June to September.