LAON (Landunum, or Lugdunum clavatum), a city of France, and capital of the department of Aisne, stands on an almost isolated hill, commanding an extensive view over the surrounding plain, 74 miles N.E. from Paris. The town is surrounded by old walls and ramparts. Among its public buildings are the noble cathedral of Notre Dame, built in the twelfth century, and surmounted by two square towers; the church of St Martin, and the Hotel de Prefecture, established in the ancient Abbey of St Jean. There are also the Hotel Dieu, a library containing 20,000 volumes, and a college. Corn and wine form the staples of its trade, and woollen cloths, blankets, hats, and worsted caps are its principal manufactures. Laon is the see of a bishop. Under the early French kings it was a place of note, and was the last possession of the Carolingian dynasty. In 1411 it was captured by the Duke of Burgundy; the English took it in 1419, and lost it in 1429. In 1594 it surrendered to Henry IV.; and in 1814 it was the scene of the defeat of the French under Marmont, by the allied army under Blücher. Pop. (1851) 8043.