A W. department of France, in Brittany, bordering on the bay of Biscay and the departments of Morbihan, Ille-et-Vilaine, Maine-et-Loire, and Vendee; area, 2,654 sq. m.; pop. in 1872, 602,206. The coast line is about 60 m. long, and broken by a number of bays. The interior is level, with the exception of a line of low hills in the north. The department is watered by the Loire and its tributaries the Sevre-Nantaise, Acheneau, and Erdre. The Vilaine touches the department on the N. W. border, and there are several less considerable streams. Grand-Lieu, formerly the largest lake in France, situated near the left bank of the Loire, with which it communicated by the Acheneau, has been recently drained. The principal minerals are coal, iron, lead, tin, slate, granite, quartz, mica, kaolin, and feldspar. The soil is generally fertile. The chief products are wheat, rye, buckwheat, mixed grain, barley, and wine. The pastures are excellent, and cattle of good breed and horses are numerous. The principal manufactures are linen, cotton, and woollen goods. Ship building is extensively carried on at Nantes, Paimbaeuf, and Pellerin. On the coast there are large fisheries. The commerce with North and South America, Africa, and the East and West Indies is important.

It is divided into the arrondissements of Ancenis, Chateaubriant, Nantes, Paimbceuf, and Savenay. Capital, Nantes.