The Château de Chenonceau (French: [ʃa.to də ʃə.nɔ̃.so], also spelled Chenonceaux) is a French château spanning the River Cher, near the small village of Chenonceaux in the Indre-et-Loire département of the Loire Valley in France. It is one of the best-known châteaux of the Loire valley.
The estate of Chenonceau is first mentioned in writing in the 11th century. The current château was built in 1514–1522 on the foundations of an old mill and was later extended to span the river. The bridge over the river was built (1556-1559) to designs by the French Renaissance architect Philibert de l'Orme, and the gallery on the bridge (1570–1576) to designs by Jean Bullant.
An architectural mixture of late Gothic and early Renaissance, Château de Chenonceau and its gardens are open to the public. Other than the Royal Palace of Versailles, it is the most visited château in France.
The château has been classified as a Monument historique since 1840 by the French Ministry of Culture. Today, Chenonceau is a major tourist attraction and in 2007 received around 800,000 visitors.
In the 13th century, the fief of Chenonceau belonged to the Marques family. The original château was torched in 1412 to punish owner Jean Marques for an act of sedition. He rebuilt a château and fortified mill on the site in the 1430s. Jean Marques's indebted heir Pierre Marques found it necessary to sell.