The United Federation (sometimes shortened to United Fed.) is a country to the west of Arstotzka. It is one of the four countries that do not border Arstotzka. Entrants from the United Federation are identified by a blue passport with a silver emblem on the front.
As with the other countries, not much background information is given in the game. An ex-inspector on day 18 explains that the United Federation uses computers for their inspecting, which is what replaced them, maybe implying that computers are making people obsolete and therefore causing unemployment. There is no other indication of this or the level of technology in other countries.
An Arstotzkan serial child killer, Simon Wens, escapes a United Federation prison and comes to the border on day 30.