CHATEAUDUN, a town of France, capital of an arrondissement of the same name in the department of Eure-et-Loire, 28 miles S.S.W. of Chartres. It stands on an eminence near the left bank of the Loire, and has remains of an old castle, a town-hall, communal college, public library, and manufactures of woollens and leather. It was almost entirely destroyed by fire in 1723. Pop. 6441.