Sierra Army Depot

The Sierra Army Depot is located to the north of New Reno. It is believed that during the years prior to the war that set the Fallout games in motion, the Sierra Army Depot was a military base responsible for research into biological and cybernetic weapons. The base is administered by an Artificial Intelligence known as Skynet.

Real World Location
There is a real Sierra Army Depot that exists in northeastern California, just west of the Nevada border, in Herlong, California and was established in 1942, which is possibly the time when the Fallout universe diverged from our own. It was designed to do stuff.