Idaho, since 1890 one of the United States, is situated between the 42d and 49th parallels of latitude, and mainly between the 111th and 114th meridians of longitude. In shape it is an irregular trapezoid. Its maximum length is about 490 statute miles; its breadth varies from about 42 miles at the 'pan-handle' which forms the northern part, to 300 miles along the southern boundary. Its area is about 84,800 sq. m.
One of the main ranges of the Rocky Mountains, in various parts called the Cabinet, Cœur d'Alene, and Bitter Root mountains, forms the north-eastern boundary, separating Idaho from Montana. In the southern part this range is a portion of the continental divide between the Atlantic and Pacific oceans. About 70,000 sq. m. of the territory is situated in the drainage basin of the Columbia River; the remaining part lies in the Great Basin, its surface waters flowing into Great Salt Lake.
A comparatively small area in the south excepted, the entire surface is rugged and mountainous. In addition to the high range on the north-eastern border spurs of this range traverse the territory in a direction generally east and west. Of these Salmon River Mountains are perhaps the most noteworthy, as they separate what is popularly known as Northern Idaho from the plateau-region in the central and southern part. All these ranges are high, their summits reaching elevations of 10,000 feet and upwards. The average altitude of the territory is about 5000 feet. The lowest level is the valley of Snake River, which at Boise City is 2000 feet above the sea-level. In the south are a number of irregular ridges largely shaped by erosion, locally known as the Bear River Mountains, Goose Creek Mountains, South Mountains, Black-foot Range, &c. A part of the plateau-region is included in the great lava flood which occurred in comparatively recent geological times, and which is still noticeable in the cliffs and mesas that diversify the surface.
Snake River—also known as Shoshone, and as Lewis River—drains by far the largest part of the territory. Its course (about 850 miles in length) lies in a valley remarkable for scenic beauty. In various places the valley widens out into broad savannas susceptible of a high degree of cultivation. The open valleys alternate with narrow cañons through which the river flows in dalles and cataracts. This river is navigable from the mouth of Powder River to Salmon Falls, a distance of 200 miles. Salmon River, one of the largest tributaries of Snake River, drains the central part. The character of its valley is much like that of the latter. Clearwater, Payette, Boise, Weiser, Bruneau, Malade, and Goose rivers are tributaries, important mainly for the fertile lands which flank their courses. Pend d'Oreille, or Clarke's Fork, drains Northern Idaho. Its main tributaries are Cœur d'Alene and St Joseph rivers. Dalles, cascades, and cataracts characterise all the rivers of the territory. Shoshone Falls almost rival those of Niagara in grandeur.
There are two lake-regions: one in the panhandle, the other in the south-east. The former includes Pend d'Oreille, Cœur d'Alene and Kaniksu lakes; the latter, John Day and Bear lakes. The surplus waters of Bear Lake flow through Bear River into Great Salt Lake. These lake-regions abound in game, and are perhaps the finest hunting-grounds in the United States.
Among the wild animals are the grizzly bear, two species of brown bear, the black bear, raccoon, panther, badger, wolf, fox, and coyote. Fur-bearing animals are represented by the lynx, mink, and beaver. The bison, once common, is now rarely if ever seen. The moose and elk are occasionally met with. Deer of two species and antelope are numerous. The Rocky Mountain sheep is found in the Cœur d'Alene Mountains.
Vegetation is abundant in the northern and central parts, but somewhat deficient in the arid lands of the south. Forests of conifers, including white, yellow, black or lodge-pole, and sugar pine, as well as several species of cedar and spruce, cover the western slopes of the Bitter Root and Cœur d'Alene mountains. These forests embrace a wealth of timber not surpassed by any other equal area on the continent. Fir, tamarack, and larch are also abundant. In the central and southern part the forests give place to extensive mesas overgrown with sage brush, and rolling lands covered with bunch grass. The river-valleys are dotted with occasional groves of cottonwood and thickets of wild fruits, such as the blackberry, wild currant, salal, and fox-grape.
The mineral wealth of the state consists chiefly in its mines of silver, lead, gold, and copper, productive in the order named. The output of these metals has sometimes reached nearly $20,000,000 in a year. Coal of good quality has been discovered in seven of the eighteen counties. In the basin-region of the south-east soda, gypsum, sulphur, and minerals common to lacustrine deposits abound. Mineral springs are numerous.
The climate is exceedingly healthy. The extremes of temperature rarely range beyond 0° and 90° F., except in regions of great altitude. The rainfall, abundant in the north, is deficient in the south, so that irrigation is necessary to ensure full crops. The agricultural products, stock and farm, aggregate well over $10,000,000. Grain-farming is of necessity confined to the narrow river-valleys, and, as a whole, the territory is better adapted to stock-raising than to cultivation. The crops are largely moved by wagon-trains and river-boats, but there were in 1890 about 1000 miles of railway.
Idaho, constituted a territory in 1863, received its present limits in 1868, and in 1890 was raised to the rank of state. Gold was first found in 1852, and raised in paying quantities in 1860. The population, distributed mainly along the river-valleys of the south and west, was returned at 14,999 in 1870, and 32,610 in 1880; in 1890 it was 84,385, about one-fifth consisting of people of the Mormon faith. There are also upwards of 10,000 Indians not included in the foregoing numbers. The public schools and religious and charitable institutions are well supported.
Boise City, the capital and largest city, had in 1890 a population of 2311. Montpelier and Weiser came next in size.