CHATEAUDUN, a town of north central France, capital of an arrondissement in the department of Eure-et-Loir, 28 m. S.S.W. of Chartres. Pop. (1931) 6,050. It stands on high ground near the left bank of the Loir. The streets radiate from a central square, the town being replanned after fires in 1723 and 187o.
Chateaudun (Castrodunum), which dates from the Gallo Roman period, was in the middle ages the capital of the countship of Dunois. The château was built in great part by Count Jean and his descendants. Founded in the loth and rebuilt in the 12th and I 5th centuries, it consists of a principal wing adjoined by a chapel. To the left of the courtyard rises a I2th century lofty keep. The church of La Madeleine dates from the 12th century; the build ings of the abbey to which it belonged are occupied by the sub prefecture, the law court and the hospital. St. Valerien, St. Jean and the ruined chapel of Notre-Dame du Champde are mediaeval in date. There is a tribunal of first instance. Flour-milling, tan ning and leather-dressing, and the manufacture of silver jewellery and machinery are carried on. Trade is in cattle, grain, wool and hemp.