In 1904 the U.S. Reclamation Service had big plans to turn the deserts of the Snake River Basin into farmland with irrigation water from the Snake River. One of their preparations was to drill a well to provide water for workers on the projects. That year the well was dug, and Rupert began to grow around it. Within a year, there were 64 businesses operating in buildings surrounding the square where the well was located, as well as a school with 100 students.
Wellfirst was the original name of the settlement. But mail was delivered by a man named John Henry Rupert. The mail was brought in a bag with the name Rupert on it, and the residents all searched through the bag for their mail. When the post office was established in 1905, Rupert was the name chosen.
As of the year 2000, Rupert has grown to 5,645 residents, and is one of the flourishing cities of the area. It is the county seat of Minidoka County, and it's largest city. Farmland surrounds the city in all directions.
Rupert lies in the middle of the Snake River Basin, in an agricultural region known as Magic Valley. The Snake River passes a few miles to the south, and provides irrigation water which transformed the desert to a rich farmland. The land is flat to the horizon on the east and west, but mountains can be seen to the south, and on a clear day, the Sawtooth Mountains are visible far to the north.
The railroad passes diagonally through Rupert from northeast to southwest, dividing the city in half, and making lots of odd intersections in a town otherwise laid out on a north-south, east-west grid. State Highways 24 and 25 run parallel to the railroad, following what used to be U.S. Highway 30. The routes split at the edge of the town, with Highway 25 following an east-west route, and Highway 24 following the diagonal route of the railroad. Interstate 84 passes by a couple miles to the south.