Isere, a S. E. department of France, in Dauphiny, bounded W. and N. by the Rhone, which separates it from the departments of Loire, Rhone, and Ain, and on the E. and S. bordering on Savoie, Hautes - Alpes, and Drome; area, 3,200 sq. m.; pop. in 1872, 575,784. It is named from the river Isere (anc. Isara), which flows through it generally S. W. from Savoie, passes Grenoble, and falls into the Rhone near Valence, Drome, after a course of 180 m., for more than 80 of which it is navigable. The surface of the department in the south is very mountainous, but in the centre and north it frequently expands into extensive plains. There are at least 20 mountain peaks, the lowest over 6,000 ft. high, and the most elevated, belonging to the Pelvoux group, on the border of Hautes-Alpes, over 13,000 ft. The soil of the lowlands is in general very fertile. Agriculture is in an advanced state. The quantity of wine made annually averages over 5,000,000 gallons; that made in the valley of the Rhone has been long celebrated. The production of silk is an important branch of industry. There are mines of iron, copper, lead, and coal; and gold, silver, platinum, zinc, and antimony are found. The staple manufactures are hardware, linens, and cotton yarn.

The department is divided into the arron-dissements of Grenoble, Saint-Marcellin, La Tour-du-Pin, and Vienne. Capital, Grenoble.