Ille-Et-Vilaine (a N. W. department of France, in Brittany, bounded N. by the English channel, and bordering on the departments of Manche, Mayenne, Loire-Inferieure, Morbi-han, and C6tes-du-Nord; area, 2,596 sq. m.; pop. in 1872, 589,532. It is named after its principal rivers, the Ille and Vilaine, the latter flowing "W. and S. W. through this department and Morbihan to the Atlantic, and partly navigable, and the former joining it from the north at Rennes. It is traversed from W. to E. by the Armoric hills or Menez mountains. The surface is irregular, and the soil generally poor. Flax and hemp are extensively cultivated; tobacco is grown to some extent, as are grapes and other fruit. The fisheries are important, and excellent oysters are found in the bay of Cancale. Several iron mines are worked; slate, quartz, limestone, and granite are quar-. ried; lead and copper ore are found; mineral springs are numerous. The manufactures consist chiefly of coarse linen and sail cloth. The coasting trade is active. It is one of the poorest French departments.

It is divided into the arrondissements of Rennes, Fougeres, Monfr-fort, St. Malo, Vitre, and Redon. The principal seaport is St. Malo. Capital, Rennes.