Châteaubriant is a town in western France, about 350 km southwest of Paris, and one of the three sous-préfectures of the Loire-Atlantique department. Châteaubriant is also situated in the historical and cultural region of Brittany, and it is the capital of the Pays de la Mée.
Its inhabitants are called Castelbriantais, and the commune of Châteaubriant proper had 12,067 inhabitants in 2015, while its small urban area numbered 24,496 inhabitants in 2015.A part of the traditional province of Brittany, Châteaubriant also lies on the threshold of Anjou, and it was an important stronghold in northwestern France during the Middle Ages. The town appeared during the 11th century, around a castle and a priory. A fair, which still exists, was also founded in 1050. Châteaubriant played a certain role during the Mad War between France and Brittany and became a significant cultural centre in the 16th century, when the Renaissance château was built in the medieval fortress.