The United States Penitentiary, Administrative Maximum Facility (ADX) is an American federal supermax prison for male inmates located in Fremont County, Colorado. It is unofficially known as ADX Florence, Florence ADMAX, Supermax, or the Alcatraz of the Rockies. Part of the Florence Federal Correctional Complex, which is operated by the Federal Bureau of Prisons (BOP), a division of the United States Department of Justice, houses the male inmates in the federal prison system who are deemed the most dangerous and in need of the tightest control. ADX also includes an adjacent minimum-security camp that, as of March 2014, houses more prisoners than the supermax unit.