ADX Prison: Cells, Inmates, and the Cunningham Settlement

ADX Florence is the only federal supermax prison in the United States, a purpose-built facility in Fremont County, Colorado that holds roughly 405 inmates the Bureau of Prisons considers too dangerous, too influential, or too high-profile for any other institution. Officially the United States Penitentiary Administrative Maximum Facility, it sits about two hours south of Denver and has operated since November 1994. Inmates spend 22 to 24 hours a day alone in concrete cells. No one has ever escaped.

Why the Federal System Built It

On October 22, 1983, two correctional officers at USP Marion in Illinois were murdered in separate attacks on the same day, both carried out by members of the Aryan Brotherhood. Marion was the toughest federal prison at the time, and the killings exposed a problem the Bureau of Prisons could not solve with existing facilities: even maximum-security general population settings couldn’t protect staff from the most violent inmates. Marion went into permanent lockdown, becoming the prototype for what would be called “supermax.”

The Bureau concluded it needed an institution designed from the ground up for isolation and control. Construction began in the early 1990s, and ADX opened as part of the Florence Federal Correctional Complex, which also includes a high-security penitentiary and a medium-security facility on the same campus.¹ Authority over federal prison management rests with the Attorney General under 18 U.S.C. § 4001.²

Inside a Cell

A standard cell at ADX measures roughly seven by twelve feet, smaller than a parking space. The furniture is poured concrete: a fixed bed slab, a small desk, and a stool. The only other fixtures are a stainless steel combination sink and toilet, a shower with an automatic shut-off, and handles on the bed frame for attaching four-point restraints. The window is a single narrow slit, about 42 inches tall and four inches wide, angled so an inmate sees only sky and can’t form a mental map of the facility.³

Meals arrive through a closable slot in a solid steel exterior door. An interior cell door sits behind that one, creating an airlock-style chamber. The design means an inmate can go days without seeing another person’s face. Any movement involves multiple officers and heavy restraints. Internal corridors are broken by reinforced steel doors that divide the building into isolated sectors, and automated systems control door openings so two inmates never move through the same space at the same time.

Outdoor recreation for the most restricted inmates happens in narrow, empty concrete pits. General population units have a larger concrete yard with a caged ceiling, divided into individual cages where inmates can see and speak with a limited number of others but cannot touch. Federal regulations require control unit inmates to receive at least seven hours of weekly out-of-cell recreation and exercise, along with access to education, legal materials, counseling, and medical services.⁴

The Housing Units

ADX isn’t one uniform lockdown. Daily life varies sharply depending on which unit holds an inmate.

Range 13 is a four-cell wing of the Special Housing Unit and the most restrictive space in the entire federal system. A psychologist at the facility once described conditions there as “a form of torture on some level.”
The Control Unit, also called Bravo Unit, is the most secure general housing unit and contains 78 cells. Inmates are isolated at all times, including during recreation, and remain in their cells 23 to 24 hours a day. Monthly behavior assessments determine whether they earn credit toward transfer.
H-Unit, or Hotel Unit, holds inmates under Special Administrative Measures imposed by judicial orders, typically terrorism-related prisoners or gang leaders whose outside communications pose a threat.
The general population units (Delta, Echo, Fox, Golf) operate similarly to the Control Unit but allow up to two hours of out-of-cell time per weekday. Inmates still spend at least 22 hours daily in their cells.
The step-down units (Joker Unit and Bravo B) are transitional housing where inmates begin limited direct contact with others as they work toward transfer out of ADX.³

Who Gets Sent There

ADX doesn’t accept inmates directly from sentencing courts. People arrive because they’ve proven unmanageable somewhere else. The usual triggers are killing or assaulting correctional staff or other inmates at lower-security facilities, running prison gangs while directing criminal operations from behind bars, attempting escape from a high-security institution, or posing an ongoing terrorism-related threat.

The placement process is governed by 28 C.F.R. Part 541, which covers control unit assignment in the federal system.⁵ The inmate gets written notice at least 24 hours before a hearing, can request a staff representative, and can present evidence and witnesses if doing so wouldn’t compromise security. A Hearing Administrator issues a written decision, reviewed by the Executive Panel and appealable to the regional director.⁶ The underlying question is whether the inmate can function in a general prison population without being a threat. Once the answer is no, ADX is the destination.

Is There a Way Out

Yes, though it’s slow and plenty of requests get denied. The Step-Down Program is designed as roughly a two-year process in four phases.

Phase 1 requires one year of clear conduct in the inmate’s current unit. A single behavioral infraction in a given month voids that month toward the required year. Phase 2 moves the inmate to the Joker Unit, an intermediate space where inmates interact with others without restraints for the first time, typically for about six months. A multidisciplinary committee reviews each inmate at least every six months.

Phases 3 and 4 take place at USP Florence High, in a unit called Bravo B or the Special Security Unit. Phase 3 brings three hours of daily out-of-cell time and 300 phone minutes per month, with computers, phones, and showers located outside the cells. In Phase 4, inmates are double-celled for at least six months and gain access to GED programming. Completing all four phases opens the door to transfer to a facility with fewer restrictions.³

Communication and Visits

All visiting at ADX is non-contact, under the Bureau’s official visiting procedures for the facility.⁷ All correspondence is screened. Phone access is extremely limited; some reporting indicates privileges as low as one 15-minute call per month for inmates in the most restrictive units.

For certain inmates, communication is restricted further through Special Administrative Measures (SAMs). The Attorney General can direct the Bureau to impose SAMs when an inmate’s communications could endanger national security, result in death or serious injury, or lead to disclosure of classified information. The restrictions can cover correspondence, phone calls, media contact, and attorney-client communications, with mail reviewed by intelligence officers and translated if needed. Attorneys representing SAMs inmates face security clearance requirements and monitoring protocols.⁸

Notable Inmates

ADX’s population reads like a roster of the most high-profile federal cases of the past several decades, covering terrorism, espionage, organized crime leadership, and mass violence:

Dzhokhar Tsarnaev, sentenced to death for the 2013 Boston Marathon bombing that killed three people and injured more than 260.
Zacarias Moussaoui, serving six consecutive life sentences for his role in the September 11 conspiracy.
Ramzi Yousef, serving life plus 240 years for masterminding the 1993 World Trade Center bombing.
Richard Reid, the “shoe bomber,” serving three consecutive life sentences plus 110 years.
Umar Abdulmutallab, the “underwear bomber,” serving four consecutive life sentences plus 50 years for the 2009 Christmas Day airline attack.
Joaquín “El Chapo” Guzmán, former head of the Sinaloa Cartel, sentenced to life plus 30 years.
Terry Nichols, serving life for his role as an accomplice in the 1995 Oklahoma City bombing.
Larry Hoover, reputed leader of Chicago’s Gangster Disciples, serving 150 to 200 years for murder.
Eric Rudolph, serving life for the 1996 Centennial Olympic Park bombing in Atlanta and other attacks.

Ted Kaczynski, the Unabomber, and Robert Hanssen, the FBI agent who spied for Russia, both died at ADX’s associated medical facility in recent years.

Mental Health and the Cunningham Settlement

The most significant legal challenge to ADX conditions came through a class action known as Cunningham v. Federal Bureau of Prisons, filed in 2012. The suit alleged that confining inmates with severe mental illness for 23 hours a day in near-total isolation violated the Eighth Amendment’s ban on cruel and unusual punishment, documenting instances of self-harm, psychotic breaks, and suicide attempts among ADX inmates who were not receiving adequate screening or treatment.

The settlement forced substantial changes. The Bureau agreed to screen all ADX inmates for mental illness, create group therapy facilities and private counseling areas, develop dedicated mental health treatment units at ADX and at facilities in Atlanta and Allenwood, Pennsylvania, and take steps to exclude inmates with serious mental illness from the facility altogether. A court-appointed monitor oversaw compliance, with the settlement’s obligations running for three years and a possible one-year extension.

Whether the settlement produced lasting change remains contested. The facility still holds people in conditions that Amnesty International and other organizations have described as prolonged solitary confinement in breach of international law, and the architecture of ADX hasn’t changed. What shifted, at least formally, is the Bureau’s obligation to identify and divert mentally ill inmates before those conditions break them further. The Bureau operates the facility under 18 U.S.C. § 4042, which charges the agency with providing for the safekeeping of federal prisoners while maintaining security and order.⁹

1
Federal Bureau of Prisons. USP Florence ADMAX
2
Office of the Law Revision Counsel. 18 USC 4001 – Limitation on Detention; Control of Prisons
3
District of Columbia Corrections Information Council. Florence ADMAX Inspection Report and BOP Response
4
eCFR. 28 CFR 541.46 – Programs and Services
5
eCFR. 28 CFR Part 541 – Inmate Discipline and Special Housing Units
6
eCFR. 28 CFR 541.43 – Hearing Procedure
7
Federal Bureau of Prisons. Visiting Procedures United States Penitentiary Administrative Maximum Facility Florence
8
eCFR. 28 CFR Part 501 – Scope of Rules
9
Office of the Law Revision Counsel. 18 USC 4042 – Duties of Bureau of Prisons