Lassay-les-Châteaux (French pronunciation: [lasɛ le ʃɑto]) is a commune in the Mayenne department in north-western France.

Later, the German occupiers further damaged the buildings, which remained deserted until Pierre de Montalembert opened the chateau to the public in the 1950s.

Work to consolidate the slope supporting one tower has also uncovered deterioration and disintegration of the rock on which the chateau stands, largely due to the effects of water and tree roots.

[10] Also listed as an Historic Monument, the Château du Bois Thibault is constructed on the old foundations of the fortress of Foulques Nerra, dating from the 11th century.

Guided tours are organised during the summer, and activities such as treasure hunts are held each year at the ruins of the chateau.

It is located in the gently rolling landscape[4] of the department of Mayenne, which forms part of the region of Pays de la Loire and close to the border of Normandy.

Visitors are attracted to the nature park's beauty and also to activities such as hiking, horse riding, mountain biking, canoeing and kayaking, and fishing.

Impressionist painter Camille Pissarro stayed in Lassay-les-Châteaux on a number of occasions and painted "Moisson à Montfoucault," during one of his visits.

The castle itself also hosts events such as medieval, aerial and musical festivals,[16] theatre productions and Concerts, candlelight tours and battle re-enactments.

They include Les Entrelacés, a festival of street arts, two Arthurian-themed treasure hunts at the Château du Bois Thibault, and a painting exhibition.

EU funding includes contributions to restoration of the large gatehouse, renovation of both drawbridges, safety upgrades to the barbican, and acquisitions of equipment such as a platform and seating stands.

The contributions are designed to enhance the development and use of the barbican for “cultural, historical and sporting activities within an exceptional setting,”[8] and thereby increase the tourist appeal of the town of Lassay-les-Châteaux.