ORENBURG, a government of south-eastern Russia, bounded on the N. by Ufa and Perm, on the S. and E. by the steppe of the Orenburg Kirghiz, and on the W. by Samara, has an area of 73,890 square miles. Situated at the southern extremity of the Urals and extending to the north-east on their eastern slope, Orenburg consists of a hilly tract bordered on both sides by steppes. The central ridge occasionally reaches an elevation of about 5000 feet ; there are several parallel ridges, which, however, nowhere exceed 2600 feet, and gradually sink towards the south. A great variety of geological formations are represented within the government. Diorites and granites enter it from the north and appear at many places from under the Silurian and Devonian deposits. The Carboniferous limestones and sandstones, as also softer Permian, Jurassic, and Cretaceous deposits, have a wide extension in the south and east. Magnetic iron, copper, silver, and lead ores, auriferous sands, and salt from the lakes constitute the mineral wealth of Orenburg, along with its very fertile "black earth," which covers wide areas around the Urals. It is traversed from north to south by the Ural river, which also forms its southern boundary ; the chief tributaries are the Sakmara and the Ilek. The upper courses of the Byelaya and the Samara, tributaries of the Kama and the Volga, also lie within the government, as well as the affluents of the Tobol on the eastern slope of the Ural range. Numerous salt lakes occur in the district of Tehelabinsk ; but several parts of the flat lands occasionally suffer from want of water. Thirteen per cent. of the surface is under wood. The climate is continental and dry, the average temperature at Orenburg being 37'4 Fahr. (4°•5 in January, 69•8 in July). Frosts of - 38°, and heats of 98° are not uncommon.

The population (900,550 in 1870) numbered 1,120,700 in 1881. The increase is largely due to immigration, an extensive tract of uncultivated land which formerly belonged to the Bashkirs having recently been purchased by the Government officials and leased to immigrants from the interior of Russia. The inhabitants are mainly Great Russians, Bashkirs (26 per cent.), and Kirghiz (about 5 per cent.). The majority belong to the Greek Church, or are Nonconformists ; 27 per cent. are Mohammedans. The chief occupations are agriculture and cattle.breeding. Although only 3-2 per cent. of the area is under crops, grain is both distilled and exported. In 1881 there were in the province 581,000 horses, 441,000 cattle, 8S0,000 sheep, and 65,000 pigs. Notwithstanding the abundance of iron and copper ore, mining is but little developed. The industrial establishments (distilleries, tanneries, flour-mills, &c.) are few, and their aggregate production in 1879 was only 5,195,000 roubles, employing about 2200 workmen. The export trade in corn, skins, and tallow is of some importance, and the fairs at Orenburg, Troitsk, and Tchelabinsk yield large returns. There are five districts, the chief towns of which are Orenburg (35,600 inhabitants), Orsk (14,350), Tebelabinsk or Tchelaba (9000). Troitsk (8300), and Verkhneuralsk (10,350).

The territory of the Orenburg Cossacks, which extends as a narrow strip up the Ural river, occupies the whole of the government east of the Ural mountains, and joins, by a narrow line of posts, the former line of blockhouses of the Siberian Cossacks, has an area of 35,820 square miles, with a population in 1880 of 290,800 Cossacks and 16,460 peasants ; 25,000 were Moslem Bashkirs.