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ADX Florence: The U.S.’s Most Secure Prison

ADX Florence, built south of Florence Colorado in 1994, is the maximum security prison in the United States prison system. Commonly referred to as a “Supermax” prison, it has 490 beds in a compound which encompasses 37 acres.

The florence co prison was designed to house prisoners deemed too dangerous or high-profile for regular incarceration, and nearly 95% of all inmates that have been sent to Florence were transfers with histories of violent behavior in other prison facilities.


ADX Florence is known for its harsh conditions; inmates are kept in solitary confinement for 23 hours a day. The hour they are allowed out is into a bigger cell with vaulted ceilings called the “empty swimming pool.” This room has a 4-inch by 4-foot skylight as the only window. It is designed to prevent the prisoners from knowing where they are, and they still spend this time alone.

For at least the first three years, prisoners are not allowed to come into contact with other prisoners at any time – anywhere on the premises. Over time, good behavior can earn inmates more “outside” time, and for the most fortunate a possible transfer back to a less-secure prison can await.

The cell furniture is limited to a desk, stool, and a bed, and each is constructed of poured concrete. The toilets are designed to shut off if plugged and the showers are on timers. Rooms may have mirrors, lights, radios, and in very rare instances televisions – but these are used as privileges based on behavior and are seldom awarded.

There is no mess hall; food is hand-delivered to each inmate by the guards. The prison has a multitude of motion detectors and cameras, 1,400 remote-controlled steel doors, and 12-foot high razor wire fences. As an added level of security, laser beams, pressure pads, and attack dogs guard the area surrounding the prison’s outlying fences.

Conditions are described as harsh, but clean and fair; it would be difficult to classify the prisoners as being “unfairly treated” given the circumstances which likely got them there. Former ADX wardens have described the place as “a cleaner version of Hell.”

The prison operates under the strategy of sensory deprivation and solitude. Inmates are left to their own thoughts, which often leads to hallucinations, memory loss, and increasingly irritable behavior.

Famous Residents

ADX Florence is home to some of this country’s most violent and evil criminals; it is also the number-one holding facility for convicted terrorists. As of the date of this article, the prison houses over 400 violent criminals including those involved in the 1993 World Trade Center bombing and 2001 World Trade Center Attacks.

There are other notable criminals such as the Unabomber Ted Kaczynski, shoe bomber Richard Reid, Oklahoma City bomber accomplice Terry Nichols, Olympic Park bomber Eric Rudolph, and Soviet spy Robert Hanssen (all pictured above).


One of the most famous residents is Thomas Silverstein (at left), a convicted murderer and former Aryan Brotherhood leader who has committed four additional murders while imprisoned.

Silverstein currently holds the record of being the longest resident of solitary confinement in the United States prison system, having been in solitary since 1983. Silverstein is often credited with being one of the reasons the ADX Supermax was designed due to his uncontrollable activities in other prisons.

Defenders of the Supermax prison point out that criminals housed inside have previously shown no regard for human life on multiple occasions, with many having committed murders in other prisons around the country in addition to their initial heinous crimes.

Historically, the addition of another life sentence to a prisoner who already has one hasn’t proved successful. Harsher penalties were needed to restore order and deter prisoners from killing prison guards. The threat of being transferred to solitary confinement at ADX Florence is the best deterrent in the prison system The United States has against violent crime.

Typical accomodations:



Satellite & Map of ADX Florence: click here