The United States Penitentiary Administrative Maximum Facility (ADX) is a supermax prison in Florence, Colorado, USA. It is unofficially known as ADX Florence, Florence ADMAX, Supermax, or The Alcatraz of the Rockies. It is operated by the federal government and is part of the Florence Federal Correctional Complex (FCC). ADX houses the prisoners who are deemed the most dangerous and in need of the tightest control. It is the highest level security federal prison in the United States, and generally considered to be the most secure prison in the world.