The construction of the Château of Chambois is probably attributable to William de Mandeville, loyal to Henry II Plantagenet, in the second half of the XIIth century. Originally surrounded by an outer wall destroyed around 1750, this château was given, after 1204, by the King of France Philippe Auguste to his Marshall Henry Clément. The rectangular keep (21.40 m x 15.40 m to the outside) is the best preserved in Normandy. Assembled in small irregular units with seals sometimes forming a form of coating, its four walls are intact and rise to 25.70 m, their ridge being equipped in the 14th century with a gallery of machicolation and crenellations. The four angles are reinforced with square turrets in cut limestone, slightly protruding, that makes them ressemble buttresses. Placed on the great south-east side is found a smaller construction that accommodated the entrance, located on the first floor.
The keep is split into three floors: a windowless ground floor and two other levels pierced, on the north-west face, by a gemeled window. Each of them consisted of a single room devoid of vaulting whose flooring rested on cornices with carved brackets, or on the wall supports and wooden poles. Each floor had a large chimney.