CHATEAUBRIANT, a town of western France, capital of an arrondissement in the department of Loire-Inferieure, on the left bank of the Chere, 40 M. N.N.E. of Nantes by rail. Pop. (1906) 5969. Chateaubriant takes its name from a castle founded in the 1th century by Brient, count of Penthievre, remains of which, consisting of a square donjon and four towers, still exist. Adjoining it is another castle, built in the first half of the 16th century by Jean de Laval, and famous in history as the residence of Francoise de Foix, mistress of Francis I. Of this the most beautiful feature is the colonnade running at right angles to the main building, and connecting it with a graceful pavilion. It is occupied by a small museum and some of the public offices. There is also an interesting Romanesque church dedicated to St Jean de Bere. Chateaubriant is the seat of a subprefect and has a tribunal of first instance. It is an important centre on the Ouest-Etat railway, and has trade in agricultural products. The manufacture of leather, agricultural implements and preserved angelica are carried on. In 1551 Henry II. signed an edict against the reformed religion at Chateaubriant.