Château de Château-Gontier, Medieval castle ruins in Château-Gontier-sur-Mayenne, France.

Château de Château-Gontier consists of medieval castle ruins in the town center. The stone structures date primarily from the 13th century and sit along Theatre Street.

The castle was founded in 1007 under Fulk Nerra of Anjou as a defensive structure against Breton territorial claims. Later, Renaud I expanded the fortress, which led to the growth of the town itself.

The name Château-Gontier comes from Gontier, the villicus of Count Fulk Nerra who was entrusted with guarding the castle founded in 1007. The town grew around this fortress at the northern edge of Angevin territory, and the name has stayed with it ever since.

The ruins are located in the town center and are easily accessible on foot. The site is open to the public, allowing visitors to view the remains at any time.

The name Gontier belonged to the count's villicus, the officer Fulk Nerra entrusted with guarding the castle, not to a lord of the town. The 1037 charter notice lists the fort's construction in 1007, the tower begun by Fulk and finished by Renaud I, and the monks' grant of a quarter of their Bazouges courtyard.