TEREK (Russ. Terskaya oblast), a Russian government of Caucasia, situated to the north of the main Caucasus chain. It is bounded by Stavropol on the N., by the Caspian Sea and Daghestan on the E., by Tiflis and Kutais on the S., and by Tchernomorsk and Kuban on the W. It has an area of 23,548 square miles. From Mt Elburz to Kazbek the southern boundary coincides with the main snow-covered range of the Caucasus and thus includes its highest peaks; further east it follows a sinuous line so as to embrace the secondary chains and their ramifications. Nearly one-third of the area is occupied by hilly tracts, the remainder being undulating and flat land belonging to the depression of the Terek; one-half of this last, on the left bank of the river, is occupied by sandy deserts, salt clay steppes, and arid stretches unsuited for cultivation. Granites, syenites, diorites, and Palæozoic schists constitute the nucleus of the Caucasus mountains; Jurassic and Cretaceous formations rise to great heights in the secondary chains; and a series of Tertiary formations, covered by Quaternary deposits, cover a wide area in the prairies and steppes. A group of mineral springs occurs about Pyatigorsk (q.v.)

The climate is continental. The mean annual temperatures are 49·6 Fahr. at Pyatigorsk (1850 feet above the sea; January 39°, July 70°) and 47°·7 at Vładikavkaz (2230 ft; January 23°, July 69°), but frosts a few degrees below zero are not uncommon. The mountain slopes receive an abundance of rain (37 in.), but the steppes suffer much from drought (rainfall between 10 and 20 in. ). Nearly the whole of the government belongs to the drainage area of the Terek, but the north-west corner is watered by the upper tributaries of the Kuma. The Terek rises at the height of about 8000 feet in the glaciers of the Kazbek on the southern slope of the main chain of the Caucasus, which it pierces by the Darial gorge to the south of Vładikavkaz after having received several dons or streams (Res, Guzel, Fiag, Ar). In 53 miles it descends nearly 6000 feet. A few miles above Vładikavkaz it is 2068 feet above sea-level, at Mozdok 441 feet, and it is 29 feet below the Black Sea at Kizlyar. From Vładikavkaz it pursues a north-easterly direction before taking its eastward course; it seems most probable that at a recent epoch (Post-Pliocene) it joined the Kuma and perhaps the Manytch instead of flowing into the Caspian. In the lower part of its course it flows at a higher level than that of the neighbouring plains, and is kept in its bed by dams. Inundations are frequent and cause great destruction. The delta begins at Dubovka (50 miles from the Caspian), and at this part the river frequently changes its bed. The Old Terek is no longer navigable, the chief current being directed northwards into the New Terek. Several canals made by the Cossacks supply water for the irrigation of the neighbouring fields. Its chief tributaries are the Sunja on the right, and the Tcherekh, the Baksan, and the Malka, in its upper course, on the left. The population of the government in 1884 was 615,660; of 606,500 inhabitants returned in 1883, 238,230 were Little and Great Russians, 1230 Georgians, 18,500 Armenians, 4300 Germans, 2570 Poles, 4780 Jews, 23,630 Ossets, 194,480 Tchetchens and Ingushis, 72,160 Kabardians, 9130 mountaineers of the Avarian stem, 25,360 Kumyks, 1770 Tatars, 6270 Nogais, 2470 Kalmucks, and 1620 Persians. Out of these 239,500 were reckoned as belonging to the Greek Orthodox Church, 336,460 were Mussulmans, 17,730 Gregorian Armenians, and the remainder Protestants, Catholics, and Jews. Owing to the great fertility of the soil in the well-watered districts, agriculture is the chief occupation. In 1882 the crops, although below the average, yielded 967,000 quarters of corn, 268,000 bushels of potatoes, 6,750,000 gallons of wine, and tobacco to the value of £18,000. Cattle breeding is extensively carried on in the steppes, and there were in the same year 118,630 horses, 582,800 cattle, and 1,226,400 sheep; murrains, however, are frequent, and cause great loss. Manufactures occupy only 3371 persons, and their yearly production hardly reaches £300,000 in value. Petty trades are rapidly spreading in the villages. Trade suffers from want of good roads. The railway from Russia to the Caucasus has not yet (1887) got beyond Vładikavkaz. The military and other chief roads have an aggregate of only 1300 miles. The exports are limited to corn, wine, cattle, and some raw produce.

The government is divided into six districts, the chief towns of which, with their populations in 1883, were Vładikavkaz (32,340), the capital, Georgievsk (4250), Groznyi (6280), Kizlyar (8780), Mozdok (8380), and Pyatigorsk (11,120).