IDAHO, a State in the 'Western divi sion of the North American Union; bounded by Montana, Wyoming, Nevada, Oregon, Washington and British Colum bia; admitted to the Union July 3, 1890; number of counties, 41; capital, Boise; area 84,800 square miles; pop. (1900) 161,772; (1910) 325,594; (1920) 431, 866.
Topography.—The surface of the State is exceedingly mountainous. The Rocky Mountains form the N. E. boundary sep arating Montana from Idaho, and send out spurs in a W. direction extending to the Sierra Nevadas. The principal ranges are the Salmon, Bitter Root, Bear River, and Saw Tooth. The Sal mon range extends along the Salmon river and reaches an altitude of 12,000 feet; the summits being rugged and sev eral being covered with snow. The Goose Creek and Bear River mountains extend along the S. portion of the State. Three-fourths of the State—the S. por tion—is arid, agriculture being practiced only by means of irrigation. Thc -soil is very fertile and the water supply ...bun dant. The principal irrigated sections of the State are in the Bear, Snake, Boise, Payette and Weiser river valleys. These valleys lie at an altitude of from 700 to 5,000 feet. The Snake river, a tributary of the Columbia, and the Wood, Bruneau, Boise, Payette, Weiser and Salmon rivers, its principal branches, form the drainage system of the S. portion of the State; the princi pal rivers of the N. part are the Spo kane, St. Joe, St. Mary's, Clearwater, Cceur d'Alene, Priest, and North Fork of the Columbia. The entire State drains into the Columbia with the excep tion of a small portion in the S. E., which is drained by Bear river into the Salt Lake basin. A large area in the S. portion is drained by streams which sink a short distance from the mountains (the lost river drainage system) and find an outlet to the Snake river by sub terranean channels. There are numer ous lakes, including the Pend d'Oreille, Cceur d'Alene, Bear, Henry, and Payette lakes. There are many beautiful wa terfalls in the State, the Snake river having four important ones, namely, Shoshone, a 210-foot fall, Twin, Salmon, and American Falls. The mean eleva tion of the State is about 4,700 feet.
Geology.—Most of the State is cov ered with Azoic, Eozoic, and Tertiary formations. Numerous fossils have been found, including the remains of the mas todon, elephant, tapir, monkey, alligator, and saurian families. Large portions
of the State are of recent volcanic for mation, and the whole region is noted for its geysers, steam and soda springs and natural hot baths.
Soit.—The soil is largely of volcanic origin, and is very fertile when water is applied. The mountains are for the most part covered with forests, which are largely evergreen. The S. counties are covered with sage plains which, un der irrigation, are well adapted to ag riculture. The N. portion of the State and the upper portions of the Boise, Weiser, and Payette valleys are cov ered with dense forests, the principal timber being white and yellow pine, fir, cedar, spruce, hemlock, and tamarack.
Mineralogy.—Gold, silver, and lead oc cur in abundance throughout all the mountains in the State. Large bodies of gold-bearing gravel are found along the Snake, Salmon, and Boise rivers, the Boise basin being noted for its aurifer ous gold deposits. About one-third of the lead mined in the United States comes from the Cceur d'Alene district. The production and value of the prin cipal metals in 1917 was as follows: lead, 196,780 tons, valued at $33,846,119; zinc, 38,927 tons, valued at $8,145,122; cOpper, 7,827,574 pounds, valued at $2, 136,928; silver, 12,029,338 fine ounces, valued at 89,912,175; gold, 38,933 fine ounces, valued at $804,809. The total value of the mineral products of the State in 1917 was $55,244,026.
Agriculture.—The N. part of the State is noted for its wheat. Owing to the sheltered location of many of the irri gated valleys agricultural products cover a wide range. All cereals and the or dinary garden vegetables and small fruits are grown. Peaches, pears, ap ples, apricots, and prunes are the prin zipal products of horticulture. The mountains of the S. portion afford ex cellent pasturage and, with irrigation, the plains of the Snake river and its tributary valleys are rapidly being con verted into cereal fields. The produc tion and value of the principal crops in 1919 was as follows: corn, 840,000 bush els, valued at $1,386,000; oats, 7,700,000 bushels, valued at $7,546,000; barley, 3,360,000 bushels, valued at $4,704,000; wheat, 18,705,000 bushels, valued at $38, 345,000; hay, 1,625,000 tons, valued at $35,750,000; potatoes, 5,400,000 bushels, valued at $8,154,000.