For five centuries, following the marriage of Jeanne de Gratot to Guillaume d’Argouges, the château belonged to the Argouges family. In 1439 Jean d’Argouges sold the port of Granville to the English, thus giving them control of Mont-St-Michel. This sale brought dishonor on the Argouges family but in the following century they redeemed the family name through appropriate marriages and proved their loyalty to the King of France.
A small three-arched bridge over the moat leads to the entrance gatehouse and then the inner courtyard. On either side are the bare walls of the service buildings; to the west are the ruins of a square corner tower. Within the courtyard from the left to right are the 18th century pavilion and the 17th century main building, flanked by the Round Tower, and the Fairy’s Tower with the North Tower to the rear.
Two flights of steps lead up to the entrance of the now roofless former living quarters. The ground floor was lit by tall windows and the upper floor by dormers.
This early 15th century round tower is quite medieval in appearance. The narrowing of the staircase as it moved upwards was devised to hinder an attack as only one person could pass at a time. At the top of the tower is a guards' room where remnants of medieval wall paintings may still be seen. The entrance to the basement is at the foot of this tower.
Stout piers support the groined vaulting of these fine cellars. The masonry is composed of stones placed edgewise. The late 15th century tower, now called the Fairy’s tower, is reinforced by a powerful buttress. It is octagonal at the base but becomes square at the top and is crowned by a saddleback roof. The wall head is decorated with gargoyles and a balustrade.
This corner tower, the only part of the medieval castle that remains, probably dates from the late 13th or the early 14th century; the door has been walled up.
One of the rooms in these 16th century outbuildings hosts an exhibition on the château, its construction and ongoing restoration.