Established January 28, 1913 with its county seat at Rupert. Named directly for the first settlement, Minidoka, a railroad siding. The name is Indian, but the exact meaning is in dispute. Some believe that Minidoka means "well, spring" but there was not a source of water such as a well or spring until 1946. Others say the word is Shoshoni and means "broad expanse," because the broadest portion of the Snake River Plain lies here.