BOISE, the capital and largest city of Idaho, United States, and the county seat of Ada county; in the south-west part of the state, 2,7ooft. above sea-level and surrounded by peaks of the Boise range ; on the Boise river, the Lincoln highway and the Oregon Short Line of the Union Pacific railway system. It has a municipal airport and air-mail service. The population was 5,957 in 19oo; 21,393 in 192o, after several annexations of terri tory; and was 21,544 in 193o.
Boise is a local headquarters of the Federal Government as well as the administrative centre of the State, and is the trade centre for a large irrigated region, shipping chiefly wool, hides and fruit. There is a United States assay office and a land office, Federal courts (circuit and district), and a veterans' hospital, which occupies the former military post of Ft. Boise. The State school for the deaf and blind, the state soldiers' home and the state penitentiary are located here. The annual wholesale business of the city is estimated at $16,000,000, and the bank clearings amount to $63,000,000 a year. There are great quarries of fine sandstone near by, which have furnished material for the Capitol and other buildings. Hot water (175°) from artesian wells supplies heat for residences and public buildings and water for a swimming pool 6oft. by 25ft. in area and 3ft. to Oft. deep. A polo tourna ment is held annually. The Arrowrock dam, 2 2M. E., is 348.5ft. high (the highest in the world), with a capacity of 340,000,000 tons of water, and has a driveway across the crest.
Boise was founded in 1863, when Major Lugenbeel of the United States Army camped on what is now Government Island and began the construction of Camp Boise. It was incorporated in 1864. Between 'goo and 1 g 1 o it grew rapidly, following the ex tensive irrigation projects undertaken in southern Idaho.