Donjon de Maurepas, Medieval castle ruins in Maurepas, France.

The Donjon de Maurepas is the cylindrical stone keep of a ruined castle, 20 metres high, standing on a low motte at the eastern edge of the Yveline plateau above the Mauldre valley. Its broken top and rough grey-brown stone are visible, with ivy on the lower walls. A farm building leans against the ruins.

The fortress evolved from wooden structures to stone construction in the 12th century, serving the Lords of Chevreuse as defense against Norman raiders. Its military role ended after English forces attacked and dismantled it in the 15th century.

The name Maurepas derives from the old spelling Malrepast, tied to the Malrepast family who held the castle. The village belonged to the Abbey of Saint-Denis from the 8th century before passing to the Lords of Chevreuse. The ruined keep, 20 m high, is the last remnant of that castle and has been a listed monument historique since 1926.

The ruins can be viewed from outside since they stand within the village and remain freely accessible to visitors. Plan your visit during warmer months when it is easier to walk around the site and see its structure clearly.

The keep is the last remnant of the fortress; a farm now leans against the ruins, as the French sources note. The surviving tower is the cylindrical keep built in the 12th century, standing 20 metres high on a low motte. It was listed as a monument historique on 19 July 1926.