Prison Security Levels: Federal Tiers, Classification, and Daily Life

Prison security levels are the tiers correctional systems use to sort facilities and the people held in them by risk. The federal Bureau of Prisons uses five: Minimum, Low, Medium, High, and Administrative. Most state systems follow a similar logic with Maximum, Close, Medium, and Minimum tiers. Each level is defined by its perimeter, housing style, staff-to-inmate ratio, and how much freedom inmates have during the day. Where someone is placed depends on a point-based classification that weighs the current offense, criminal history, violence, escape history, and time left to serve, and that classification is reviewed and can shift over time.

The Five Federal Security Levels

The Bureau of Prisons classifies every federal institution by its physical security features, housing type, internal controls, and staffing.¹ As of the most recent BOP data, roughly 37 percent of federal inmates are housed at Low security, 33 percent at Medium, about 15 percent at Minimum, and 12 percent at High.²

Minimum Security

Minimum-security institutions are called Federal Prison Camps. They have dormitory housing, little or no perimeter fencing, and the lowest staff-to-inmate ratio in the system. Programming and work are the center of daily life, and inmates generally have the most freedom of movement on the grounds.¹ Many camps sit next to a larger institution or a military base. People housed here are usually serving time for nonviolent offenses, have shorter remaining sentences, no escape history, and no serious detainers.

Low Security

Low-security Federal Correctional Institutions have double-fenced perimeters, mostly dormitory or cubicle housing, and more staff per inmate than camps. Work and program components are strong, and inmates still move relatively freely within the compound during scheduled times.¹ This is the most populated level in the federal system.²

Medium Security

Medium-security FCIs have strengthened perimeters, often double fences with electronic detection, and mostly cell-type housing rather than open dormitories. Internal controls tighten noticeably: inmates move under closer supervision, and staffing is heavier than at Low. A broader range of work and treatment programs is available.¹

High Security

High-security institutions are United States Penitentiaries. They have the most fortified perimeters in the standard system, with walls or reinforced fences. Inmates live in single- or double-occupancy cells, and the staff-to-inmate ratio is the highest of any level. Movement is closely controlled, and every transition between areas involves direct staff oversight.¹

Administrative Facilities

Administrative is a category rather than a single level. It covers Federal Medical Centers for inmates with serious medical conditions, Metropolitan Correctional Centers and Metropolitan Detention Centers for pretrial detainees, the Federal Transfer Center, and the Administrative-Maximum facility in Florence, Colorado. With one exception, these institutions can hold inmates of any security category.¹

That exception is the ADX, the highest-security federal prison in the country. Inmates are typically confined to their cells for 22 to 23 hours per day, with one to two hours in a small outdoor recreation area that is sometimes canceled. Visits are rare and non-contact. The ADX holds people deemed too dangerous, predatory, or escape-prone for any other institution, and placement there comes after other options have been exhausted, not as an initial designation.

State Prison Security Levels

State systems set their own tiers, and the labels vary. Most use some version of Maximum, Close (or Close Custody), Medium, and Minimum, and some add a Trusty or Community tier at the bottom. The underlying logic matches the federal approach: physical security and supervision climb with each step up.

Maximum-security state prisons house people with histories of violence, escape attempts, or the highest assessed risk. They feature high walls or reinforced fencing, extensive surveillance, and tight control over daily movement, and some inmates spend most of the day locked in their cells. Close-security designations, used in many states as a step below Maximum, apply to people who still need near-constant supervision and rarely leave their housing area but may get slightly more program access.

Medium-security state prisons hold the widest mix of inmates. The perimeter is secure, but inside, people have more access to work, education, and recreation, and movement is supervised but less restrictive. Minimum-security state facilities resemble federal camps: dormitory housing, a focus on work and rehabilitation, and inmates considered low risk for violence and escape.

How Inmates Get Classified

Nobody picks their facility. The BOP uses a point-based scoring system that assigns each person a security level through a structured intake assessment. It weighs the severity of the current offense, criminal history score, history of violence, prior escape attempts, and time remaining on the sentence, along with medical and mental health needs and validated gang membership.³ The total determines whether the designation is Minimum, Low, Medium, or High.

Security Level Versus Custody Level

The BOP actually runs two parallel systems. The institution has a security level, which describes the physical facility. The inmate has a custody level, which describes how much freedom that specific person gets inside or outside the facility. Custody levels are Community, Out, In, and Maximum. Someone with Out custody at a Minimum camp can leave the perimeter for work details; someone with In custody at the same camp stays inside the fence line. Community custody allows halfway house placement, and Maximum custody means the tightest individual restrictions.³

Public Safety Factors

Even when the point total would qualify someone for Minimum, certain Public Safety Factors can force a higher placement. They exist because some situations carry risks that raw points do not capture:

Sex offense history requires at least Low security.
Deportable noncitizen status requires at least Low security.
Greatest severity offense, for men, requires at least Low security.
Validated disruptive group membership, for men, requires High security unless waived.
For men, more than 20 years remaining requires at least Medium, and more than 30 years, including life, requires High unless waived.
Serious escape history requires at least Medium.

Any of these factors can be waived in certain circumstances, but they set a floor the point system alone cannot push below.³

Moving Between Security Levels

An initial designation is not permanent. The BOP reviews each inmate’s classification on roughly a 12-month cycle, and changes that significantly affect the point total, such as a new disciplinary conviction or a sentence reduction, can trigger a review outside that schedule.³

Sustained good behavior and program participation are the main paths to a lower level. Completing education, drug treatment, and work assignments can reduce points. Disciplinary infractions, new charges, or verified gang activity push the other way. Transfers also happen for reasons unrelated to conduct, such as a medical need that requires a Federal Medical Center or population management across the system.

Good Conduct Time

Federal inmates serving more than one year can earn up to 54 days of good conduct time per year of the court-imposed sentence, provided they comply with institutional rules. The BOP also considers whether the inmate is working toward a high school diploma or equivalent when awarding credit.⁴ Losing good conduct time for discipline is one of the most immediate consequences of misconduct and directly pushes back a release date.

First Step Act Earned Time Credits

The First Step Act of 2018 added a separate layer of credits on top of good conduct time. Eligible inmates earn 10 days for every 30-day period of successful participation in approved recidivism-reduction programs or productive activities. Those classified as minimum or low risk for recidivism who hold that classification for two consecutive assessments earn an additional 5 days, bringing the total to 15 days per 30-day period.⁵ These credits do not shorten the sentence itself; they move people into prerelease custody sooner, either at a halfway house or on home confinement.

How Security Level Shapes Daily Life

The practical difference between levels goes well beyond fencing. What you can do each day, who can see you, and how much of your time you control all shift as security tightens.

Visitation

At Minimum and Low security, visits can take place beyond the security perimeter under staff supervision. Medium and High restrict visiting to areas inside the perimeter. Contact visits, including handshakes, hugs, and a brief kiss at the start and end of a visit, are generally permitted at all levels unless staff determine contact would create a security risk.⁶ At the ADX, visits are rare and non-contact. Inmates held in Special Housing Units face added restrictions regardless of the institution’s general level.

Programs and Movement

Minimum and Low inmates have the most access to work, vocational training, education, and recreation, and they move around the compound with relative independence during scheduled periods. Medium security introduces more structured movement, often with escorts or controlled movement times. High security involves smaller groups moving under direct supervision, with more frequent lockdowns. The ADX offers almost no communal programming. States follow the same pattern: the lower the level, the more programming and movement.

Gang Membership and Privileges

Validated membership in a gang or security threat group is one of the fastest ways to lose privileges at any level. In the federal system, validated disruptive group members face mandatory High placement.³ State systems impose similar consequences, including placement in restrictive housing, loss of contact visits, exclusion from educational and vocational programs, restricted movement, and ineligibility for certain good-time credits.

Special Housing Units Across All Levels

Every federal security level can include a Special Housing Unit, where inmates are separated from the general population. The SHU is not a security level; it is a temporary housing status that exists inside institutions of all levels. Placement there is either administrative detention or disciplinary segregation, and the distinction matters.⁷

Administrative detention is non-punitive. Staff remove someone from general population when their presence poses a safety or security concern, such as during an investigation, pending transfer, or when the inmate needs protection from other inmates. It can also happen while classification is pending. Disciplinary segregation is punitive and can only be imposed by a Discipline Hearing Officer as a sanction after a finding that an inmate committed a prohibited act.⁷ Protective custody is a common reason for administrative detention; an inmate who has been assaulted, threatened, or identified as an informant may be placed in the SHU for safety, and some people request protective custody themselves. State systems have parallel programs, with their own procedures and terminology.

For families trying to figure out where a loved one might end up, the classification system is designed to be dynamic. An initial placement reflects a snapshot of risk at sentencing, but behavior, programming, and time served all feed back into the score. People who stay out of trouble and engage with available programs generally move to less restrictive settings over time, and those who accumulate disciplinary issues move in the other direction.

1
Federal Bureau of Prisons. Federal Prisons
2
Federal Bureau of Prisons. Prison Security Levels
3
Federal Bureau of Prisons. Inmate Security Designation and Custody Classification
4
Office of the Law Revision Counsel. 18 U.S. Code 3624 – Release of a Prisoner
5
eCFR. Part 523 Computation of Sentence
6
eCFR. 28 CFR Part 540 Subpart D – Visiting Regulations
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eCFR. Part 541 Inmate Discipline and Special Housing Units