IDAHO FALLS, a city of E. Idaho, U.S.A., on the Snake river, 123 m. S.W. of the western entrance to Yellowstone park, at an altitude of 4,708 ft.; the county seat of Bonneville county. It is on the Oregon Short Line of the Union Pacific system, and on Federal highway 91, at the southern terminus of 191. The popu lation was 8,064 in 1920 (of which 9o% was native white), and by the census of 1930, 9,429. It is the shipping point and trading centre of a vast irrigated region of 1,250,00o ac., devoted to a variety of crops, and to stock-raising, wool-growing, dairying and cheese-making, bee-keeping and cattle and sheep-feeding. In or near the city are several large beet sugar factories (including the first one built in Idaho, in 1903), a seed-cleaning mill which supplies peas and beans for gardens from Maine to California, a factory which extracts hundreds of tons of alfalfa and sweet clover honey, grain elevators, flour and potato-flour mills and potato and wool warehouses.
The falls are at the head of a narrow canyon. Here a toll bridge was built in 1866, and around it grew up a supply station for the freighters travelling the Utah-Montana trail. The town was long called Eagle Rock, because an eagle had a nest on a large rock in the stream just above the bridge. It was chartered as a city in 1891.