ADX Florence
United States Penitentiary, Administrative Maximum Facility is a United States federal prison for men in Fremont County, Colorado, United States. It is operated by the Federal Bureau of Prisons, a division of the United States Department of Justice. The prison houses some of the most dangerous criminals in the United States.
ADX Florence, constructed in 1994 and opened the following year, is classed as a supermax or "control unit" prison, that provides a higher, more controlled level of custody than a regular maximum security prison. ADX Florence forms part of the Federal Correctional Complex, Florence, which is situated on of land and houses different facilities with varying degrees of security, including the adjacent United States Penitentiary, Florence High.
ADX Florence was commissioned when the Federal Bureau of Prisons needed a unit designed specifically for the secure housing of specific prisoners most capable of extreme violence toward staff or other inmates, as well as inmates deemed too high-profile or too great a security risk for even a maximum security prison. The inmates are confined for most of the day in single cells with facilities made of poured, reinforced concrete to deter self-harm, and are under 24-hour supervision, carried out intensively with high staff–inmate ratios.
Function
The institution is unofficially known as ADX Florence or "the Alcatraz of the Rockies". It is part of the Federal Correctional Complex, Florence, run by the Federal Bureau of Prisons under the United States Department of Justice. The complex includes a minimum-security camp that, held more prisoners than the supermax unit. The number of inmates has declined, and as of 2021, two housing units had closed due to low population.Florence houses male inmates in the federal prison system deemed the most dangerous and in need of the tightest control, including prisoners whose escape would pose a serious threat to national security.
Women classified as a "special management concern" due to violence or escape attempts are confined at Federal Medical Center, Carswell in Fort Worth, Texas.
History
On October 22, 1983, Thomas Silverstein and Clayton Fountain, members of the Aryan Brotherhood, fatally stabbed correctional officers Merle Clutts and Robert Hoffman at the United States Penitentiary, Marion. The stabbings took place only a few hours apart and were blamed on inadequate prison design.Federal Bureau of Prisons director Norman Carlson proposed a new facility to isolate the most dangerous, uncontrollable inmates for security and safety. Under his leadership, USP Marion was operated in permanent lockdown for 23 years, serving as a model for ADX as a control unit prison. Carlson believed that the prison would hold criminals who were desperate enough to murder corrections officers or other inmates in the hopes of being sentenced to death. He argued that as draconian as these measures were, they were the only way to deal with inmates who have "absolutely no concern for human life".
Florence opened on January 10, 1995. The county already had nine prisons, but the lure of 750 to 900 permanent jobs led residents to raise $160,000 to purchase for the new prison. Hundreds of people attended the groundbreaking for the facility, which was designed by two architecture firms in Colorado Springs and cost $60 million to build.
Inmate population
The supermax unit at Florence housed 380 male inmates as of November 2025, each assigned to one of six security levels. It is designed to house up to 474 inmates but has never been at full capacity.The facility is best known for housing inmates who have been deemed too dangerous, too high-profile, or too great a security risk for even maximum-security prisons. For example, Joseph Romano was sentenced to life in federal prison for plotting to murder the judge and federal prosecutor who helped sentence him to 15 years in prison for masterminding a coin fraud operation. While in prison, he plotted to murder an undercover officer who had taken part in the investigation. When this came to light, Romano was transferred to Florence. Another notable inmate was Robert Hanssen, who spied for the Soviet Union and Russia on and off from 1978 until his arrest in 2001. Hanssen served a life sentence there and died in 2023. His case is considered "the worst intelligence disaster in U.S. history."
The majority of current inmates, however, have been placed there because each has an extensive history in other prisons of committing violent crimes, including murder, against corrections officers and fellow inmates. These inmates are kept in administrative segregation; they are kept in solitary confinement for 23 hours a day. During their hour outside the cell, which can occur at any time of day or night, they are kept under restraint. The hour outside of the cell is for exercise and a phone call if they have earned the privilege. Their diet is restricted to ensure that the food cannot be used to harm themselves or to create unhygienic conditions in their cell. Some cells have showers, which are run on a timer to prevent flooding, further reducing the amount of handling of inmates that correctional officers have to perform.
After at least one year, depending on their conduct, inmates are gradually allowed out for longer periods. The long-term goal is to keep them at Florence for no more than three years and then to transfer them to a less restrictive prison to serve the remainder of their sentences. According to a 1998 report in the San Francisco Chronicle, Florence's main purpose is to "try and extract reasonably peaceful behavior from extremely violent career prisoners".
One cell block at Florence was once known as "Bombers Row" because a number of particularly notable terrorists, including notable domestic terrorists, were held there: Timothy McVeigh, Ramzi Yousef, Ted Kaczynski and Dzhokhar Tsarnaev.
Prison facility
ADX Florence is a complex located at 5880 Highway 67, in an unincorporated area, with a Florence, Colorado, postal address. It is located about south of Denver and south of Colorado Springs. It is part of the Federal Correctional Complex, Florence which consists of three correctional facilities, each with a different security rating.The majority of the facility is above ground, with the exception of a subterranean corridor that links cellblocks to the lobby. Each cell contains a desk, stool, and bed, constructed almost entirely of poured concrete, as well as a toilet that shuts off if blocked, a shower that runs on a timer to prevent flooding, and a sink lacking a potentially dangerous tap. Cells are also fitted with polished steel mirrors bolted to the wall, electric lights that can be shut off or dimmed by the inmate, a radio, and a television given to inmates for good behavior; as of 2018, the television system included institution-run channels featuring announcements and educational courses, a number of general and specialty news and entertainment channels, and PG-rated films shown through the CCTV system.
The 4-inch-by-4-foot windows are designed to prevent inmates from knowing their specific location within the complex. They can see only the sky and roof through them, so it is virtually impossible to plan an escape. Inmates exercise in a concrete pit resembling an empty swimming pool, also designed to prevent them from knowing their location in the facility. The pit is large enough only for a prisoner to walk ten steps in a straight line or thirty-one steps in a circle. Correctional officers generally deliver food to the cells. Inmates transferred to Florence from other prisons may be allowed to eat in a shared dining room.
The prison as a whole contains a multitude of motion detectors, cameras, and 1,400 remote-controlled steel doors. Officers in the prison's control center monitor inmates twenty-four hours a day and can activate a "panic button", which immediately closes every door in the facility, should an escape attempt be suspected. Pressure pads and razor-wire fences surround the perimeter, which is patrolled by heavily armed officers.
The facility houses inmates at six differing security levels: General Population Units, the Special Housing Unit, the Special Security Unit, the Control Unit, Intermediate/Transitional Units, and Range 13. Many of the security levels at ADX have special purposes or missions for the inmates who occupy them. The Control Unit houses inmates who have committed serious conduct violations or acts of violence at other institutions. It also houses high-level members of organizations deemed as threats, such as prison gangs. "H" Unit houses inmates who are members of terror groups so designated by the Department of Justice or who have had special administrative measures placed on them. Range 13 is a special four-cell wing within the Special Housing Unit for inmates in need of the tightest control. As of 2022, the only inmates publicly known to have been incarcerated in this unit are Ramzi Yousef and Joaquín "El Chapo" Guzmán. The two Intermediate Units house "step-down" inmates, who can earn transfer to another institution if they remain incident-free while housed in the unit. This is the only unit in ADX where inmates secure themselves in their own cells, can walk freely in their range, and associate with other inmates. From there, inmates will typically be transferred to the supermax step-down unit in USP Florence High.
The Bureau of Prisons allowed the media to take a guided tour of Florence on September 14, 2007. Attending reporters remarked on "an astonishing and eerie quiet" within the prison, as well as a sense of safety due to the rigorous security measures. 60 Minutes producer Henry Schuster said, "A few minutes inside that cell and two hours inside Supermax were enough to remind me why I left high school a year early. The walls close in very fast."
The prison has received far less criticism than comparable facilities at the state level, which tend to suffer from over-population, low staff-to-inmate ratios, and security issues. Jamie Fellner of Human Rights Watch said after a tour of the facility in 1998, "The Bureau of Prisons has taken a harsh punitive model and implemented it as well as anybody I know."