IDAHO, a north-western territory of the United States, of Wyom- was originally a part of Oregon, from which it was separated in 1863. It lies on the Pacific slope, with the exception of a small portion in its south-eastern corner, which is drained into the Great Salt Lake of Utah. It is bounded on the N. by British Columbia and N.E. by Montana; on the E. by Wyoming; on the S. by Utah and Nevada; and on the W. by Oregon and Washington. The boundaries are the meridians (111° and 117° W. long.) and the 42d and 49th parallels of N lat., except that in the N.E. the Bitterroot range separates the territory from Montana, and the Snake river forms part of the western limit. The area of the territory is imperfectly known, but may be set down approximately at 86,300 square miles. The mean elevation is about 4700 feet. The lowest point, which is on Snake river, at the mouth of the Clearwater, is about 1000 feet above the sea, while the highest mountains rise nearly to 10,000 feet. The surface is very diversified; the northern portion is largely mountainous, with several fine broad valleys. In the southern portion a large area within the great bend of the Snake river is occupied by an immense plain of basalt. South of the Snake the country is an alternation of broad valleys and narrow abrupt mountain ranges.

The principal mountains are the Bitterroot and Salmon River chains, with their spurs and subordinate ranges. They attain a height of from 8000 to nearly 10,000 feet. The Snake River plain lies south of these mountains, ex-tending east and west nearly across the territory. This is a field of basalt, seamed and crevassed, with little vegeta-tion, and that consisting principally of Artemisia. The soil here is a shifting sand; and there is little surface water, as the streams sink and flow underneath.

The principal river is the Snake, the south fork of the Columbia. It is a rapid stream with numerous falls, three of which, the American, Shoshone, and Salmon or Fishing, are very considerable. It is navigable only in its lower course. Several of the branches of the Snake, the Salmon, Clearwater, and Spokane, are large streams, but are not navigable, and are of value only for irrigation and mining purposes.

Map of Idaho.

The climate, like that of other portions of the north-western United States, is characterized by great aridity of atmosphere and slight rainfall. In the south the aridity is such that large areas are almost desert; but in the mountainous regions of the north the rainfall is much greater, and agricultural operations can be carried on to some extent without irrigation. The northern part, being principally mountainous, is covered with forests of conifers, chiefly species of pine, spruce, fir, and tamarack. In the open valleys the vegetation consists mainly of the various kinds of grasses known collectively as "bunch grass." On the Snake River plains there is little vegetable growth except Artemisia, while the country south and east of the Snake is covered with this and with grasses, with a little scattered timber (Ooniferce and aspens) on the mountains. A rough estimate gives as the area covered by forest 40,000 square miles, by useful grasses 25,000 square miles, and by Artemisia 21,300 square miles.

Though the bison formerly ranged over this whole region, it is now practically extinct. The moose is still occasionally seen, and, rarely the Rocky Mountain goat (Aploceras montanus). The wapiti, the mountain sheep (Ovis mon-tana), and various species of deer are still abundant in the mountains, while the antelope or pronghorn abounds in the plains. Grizzly, black, and cinnamon bears, the American panther, the wild cat, and the wolverine are not unfrequently met with in the unsettled regions. Among the smaller quadrupeds, the prairie dog and gopher are abundant in the valleys and on the plains. Birds of many species are plentiful, especially in the mountain regions. Of reptiles, several species of rattlesnakes and lizards, including horned toads (Phryuosoma), are characteristic of the arid plains, where they are numerous.

The southern portion of this territory has been the scene of comparatively recent volcanic action, which has covered enormous areas with basalt. The mountains of this portion are mainly of the Silurian and Carboniferous ages. The ranges of the northern portion are known to be mainly Eozoie; but the geology of that section has yet to be investigated.

The administration of the territory is in the hands of a governor, secretary, and chief justice, all appointed by the president of the United States, and a treasurer, comptroller, and superintendent of public instruction, who, as well as the members of the two houses of the legislature, are elected by the people. The territory is represented in Congress by a delegate, also elective. The population in 1880 was 32,946, distributed thus in the several counties :—
County. Population. County. Population.
Ada 4674 Nez Perce 4483
Alturas 1693 Oneida 6952
Bear Lake 3242 Owyhee 1427
Boise 3213 Shoshone 469
Total 32,946
Cassia 1315 Washington 877
Idaho 2371
Kootenai
Lemhi 2230

The principal settlements are Malade, Boise" (the capital of the territory), Idaho, Buenavista, and Silver City.

The agricultural, grazing, and mining interests of Idaho are but commencing their development. In the valleys of the southern portion the Mormons are raising abund-ant crops of cereals, with the aid of irrigation. In the valleys of the lower Snake, the Boise", Clearwater, Salmon, and Spokane rivers, wheat, oats, rye, and other grains are cultivated to some extent. Large portions of the territory are well adapted for grazing, and this is now being turned to account.

The mineral wealth has not yet, owing to difficulty of transportation, been developed to any great extent; but it is known to be important. Gold and silver are found, the former both in vein and in placer deposits. The principal vein deposits now being worked are in the Salmon River and Owyhee mountains. Placers have been worked in nearly every county of the territory, and have paid well. During the year 1880 many new and rich deposits have been discovered in the Wood River district, in the Salmon River mountains, and there has been a considerable influx of mining population.

The Utah and Northern Railroad crosses the south-eastern portion of the territory, from Utah to Montana.

The total number of Indians in Idaho is about 6000, consisting of the tribes known as the Nez Perce", Ban-nack, Shoshone, Cceur d'Alene, Spokane, Pend' Oreille, and Kootenai. They are under the control of the Government, and most are settled on reservations.