Idaho, one of the United States, organised as a territory in 1863, and formed by uniting part of the east of Washington and Oregon with slices taken from the west of Nebraska and the north of Utah, so as to make up an area of 86,294 square miles. It adjoins British Columbia to the north. Much of the surface is mountainous and woody, but there are broael and fertile valleys, especially in the north. Towards the south vast tracts are covered by recent basaltic eruptions. Many streams flow down from the Rocky, the Bitter-root, and the Salmon river chains, the largest being the Snake, the Salmon, the Clearwater, and the Spokane. The climate is very dry. Boisee, Idaho City, Malade, Buenavista, and Silver City are the chief centres of population. The mineral resources include gold, silver, copper, iron, coal, and salt, all of which have been worked profitably. The railway from Utah to Montana traverses the lower portion of the territory. It was admitted as the forty-third State of the Union in 1890.