BLACKFOOT, a city of Idaho, U.S.A., on the Snake river, Federal highway 91, and the Oregon Short Line of the Union Pa cific railway system, about halfway between Pocatello and Idaho falls, at an elevation of 4,5o2ft.; the county seat of Bingham county. The population in 193o was 3,199. It is the shipping, trad ing, and educational centre for a prosperous irrigated agricultural, grazing, and mining district, and has sugar-beet and cheese fac tories. The State insane asylum is located here. Just south of the city is the Fort Hall Indian reservation; ten miles west is the site of a Hudson's Bay Company trading post, which was the first white settlement in Idaho and one of the first west of the Rockies. About 6om N.W. is the Craters of the Moon national monument, which contains remarkable lava tunnels and caves, with fantastic formations coloured in reds and blues, and many other volcanic phenomena resulting from comparatively recent eruptions.