I. A government of Asiatic Russia, in the S. part of E. Siberia, bordering on Mongolia; area, 271,875 sq. m.; pop. in 1870, 365,810. The continuations of the Altai mountains form its S. boundary. The surface is elevated, the general level in the north and east being from 2,500 to 3,000 ft., and that in the south 1,200 to 2,000 ft. It is watered by the Angara,- Lena, and several smaller rivers, and contains Lake Baikal. It is rich in minerals, among which are gold, silver, copper, and iron. Extensive forests, furnishing excellent timber, and abounding in all kinds of game, occupy a large portion of the country; and agriculture is prosperously conducted, barley and rye being the principal crops. The pastures support great numbers of cattle and sheep. The summers are short, but very warm and generally clear, while the winters are so cold that sometimes mercury freezes. A considerable portion of the inhabitants are descendants of Russian exiles, and the majority of the natives are Mongols, Tunguses, and Buriats. II. A city, capital of the government and of E. Siberia, on the right bank of the Lower Angara, about 35 m. from its source in Lake Baikal; pop. about 30,000. It lies on both sides of the mouth of the Ushakovka, a small tributary of the Angara, and opposite the confluence of the Irkut with the latter river.

It is well built, paved, and lighted. The principal streets run parallel with the Angara, on the banks of which are the exchange, the admiralty offices and dockyards, the governor general's palace, and various government factories and workshops in which convicts are employed. In the centre of the city is a handsome public square, on which front the houses of many of the functionaries, and the guard house. The school of medicine, the gymnasium, and the former depot of the Russian American company are fine and spacious. There are many public schools, a high school for navigation, a female orphan school, a theatre, and a good bazaar. The city is fortified, and has a citadel. It contains 15 churches, and numerous convents and hospitals, and is the see of an archbishop. Nearly all the houses are of wood, neatly planked, and painted yellow or gray. The principal manufactures are woollens, linens, leather, glass, and soap. The trade of Irkutsk is important. It is the great commercial entrepot between the Chinese empire and European Russia, exporting to the latter tea, rhubarb, fruits, porcelain, paper, silk, etc, in exchange for furs, metals, and various European goods.

It has a great fair in June.