Château d'Oudon is a fortified structure located in Oudon, France. Built at the end of the 14th and beginning of the 15th century, on the site of an older structure, it was redesigned in the 16th century and restored in the 19th and 20th centuries.
The castle is located in the commune of Oudon, in the Loire-Atlantique department. It was built on a rocky outcrop overlooking the Loire Valley, which flows a few hundred metres to the south, at the confluence of a river called Le Hâvre.
The castle is built in schist and gneiss stone, the horizontal and corner ties are made of tuffeau. The keep, a major element of the monument, has the same characteristics as the Largoët fortress in Morbihan, built at the same time by Jean II de Châteaugiron, Alain de Malestroit's younger brother, but the decorative elements are inspired by those of the Loire castles. It is 32.5 metres high and topped by an octagonal turret of 7.45 metres. The walls are 3 meters thick. The machicolations are decorated with blown patterns.