YONNE, a department of central France, formed partly from the province of Champagne proper (with its dependencies, Salon ais and Tonnerrois), partly from Burgundy proper (with its de pendencies, the county of Auxerre and Avallonnais) and partly from Gatinais (Orleanais and Ile-de-France). It is bounded by Aube on the north-east, Cote-d'Or on the south-east, Nievre on the south, Loiret on the west and Seine-et-Marne on the north west. Pop. ( '930 275,755. Area 2,892 sq. miles. The highest elevation (2,00o ft.) is in the granitic highlands of Morvan. The department belongs to the basin of the Seine, except a small district in the south-west (Puisaye), which belongs to that of the Loire. The river Yonne flows through it from south to north north-west, receiving on the right bank the Cure, the Serein and the Armancon, which water the south-east of the department. Farther north it is joined by the Vanne.
The department is served chiefly by the P.L.M. railway. The canal of Burgundy, which follows the valley of the Armancon, has a length of 57 m. in the department, that of Nivernais, following the valley of the Yonne, a length of 33 miles. The department
constitutes the archiepiscopal diocese of Sens, has its court of appeal in Paris, its educational centre at Dijon, and belongs to the district of the V. army corps. It is divided into 3 arrondisse ments (37 cantons, 486 communes), of which the capitals are Auxerre, also capital of the department, Avallon and Sens; these with Chablis, St. Florentin and Vezelay are its chief towns (qq.v.). Pontigny has a Cistercian abbey, where Thomas Becket spent two years of his exile, with a 12th century church. Druyes has a 12th century château. Villeneuve-sur-Yonne has a mediaeval keep and gateways and a church of the 13th and 16th centuries. The Re naissance châteaux of Fleurigny, Ancy-le-France, Tanlay and the château of St. Fargeau, of the 13th century, rebuilt by Made moiselle de Montpensier under Louis XIV., are all noteworthy. At St. More there are remains of the Roman road from Lyons to Gallia Belgica and of a Roman fortified post. There are many megalithic monuments in the department.