What’s the difference between prison and jail?

You know how you’re watching the news, and the reporter solemnly says a criminal will be spending his or her life in jail, or will serve a 20-year jail sentence, or is languishing in prison waiting for trial?

It’s not going to happen. Let me clear this up.

In the United States, we often encounter inconsistent use of the terms, “prison” and “jail.” They are not the same thing. Accuracy in using these terms shows a higher quality of media coverage and will also improve public understanding of justice and public safety issues.

Definition: Jail

A jail is a secure facility that houses three main types of inmates:

  1. People who have been arrested and are being held pending a plea agreement, trial, or sentencing;
  2. People who have been convicted of a misdemeanor criminal offense and are serving a sentence of (typically) less than 1 year; and
  3. People who have been sentenced to prison and are about to be transferred to another facility.

Jails are operated by a county or city government. Jails are also known as detention facilities. Lockups are facilities in smaller communities where one to a few arrestees can be held for a short time pending transfer to a nearby jail/detention center.

A lot of new detainees are delivered to jails daily. Some may stay less than one day or only for a few days, until they are okayed for release in a court proceeding. Some are released after putting up bail, are released to a pretrial services caseload, are placed under supervision by a probation agency, or are released on their own recognizance with an agreement to appear in court.

A considerable number of people arriving at a jail are actively or recently drunk or high, arrive with injuries from fights/assaults that led to their arrest, and/or are mentally ill with no other place for law enforcement to deliver them. This makes the intake process challenging for the jail’s staff and its medical personnel.

Definition: Prison

A prison is a secure facility that houses people who have been convicted of a felony criminal offense and are serving a sentence of (typically) 1 year or more.

Prisons are operated by a state government or the federal government. “Penitentiary” is a synonym for prison.

The number of sentenced inmates entering prisons each day is far less than the number of people delivered at the door of U.S. jails. People who are going to prison know it in advance. They may be transferred from a jail, taken to prison from court after a conviction, or report to prison on a date set by the court.

People released from prison may be released to parole supervision or to some other type of community program. Or they may be released with no supervision at all, if they have served their full term in prison.

Where the definitions get fuzzy:

  • In six states, a state-level agency provides both jail and prison services. These states include Alaska, Connecticut, Delaware, Hawaii, Rhode Island, and Vermont. Some of these states run both jail and prison functions within the same secure facilities, and sometimes the state has separate facilities for its jail and prison populations. For details, see A Review of the Jail Function Within State Unified Corrections Systems (Krauth, 1997, U.S. Department of Justice, National Institute of Corrections).
  • In some jurisdictions, the cut-off for serving time in jail instead of prison is 2 years rather than 1 year.
  • The U.S. federal government operates several detention centers in major U.S. cities.

State, local, and federal criminal justice systems are full of minutiae, so there will be exceptions to the basics explained here.

Learn More

For some additional explanations and perspectives, see also:

  • Jails vs. Prisons. Daron Hall, Davidson County Sheriff, Nashville, Tennessee, writing in Corrections Today magazine, from the American Correctional Association.

For further thought –

In criminal justice punishment theory, people are sentenced to serve time in confinement for four basic reasons (some of which have greater proven efficacy than others):


The concept of providing treatment (such as addiction treatment) and programs (such as education and job skills training) to boost the likelihood that an inmate will not return to crime when he or she is released back to the community. (Highest efficacy. Treatment and programming make the greatest difference in changing offenders’ lives and future behavior. See, for example, reports from the Washington State Institute of Public Policy.)


The concept that putting an offender in a secure facility prevents him/her from victimizing the public again. (Reasonable efficacy – this works while the offender is in custody.)


The concept that an offender who serves time is paying society back for the harm done in the crime. (Low efficacy. Society gains nothing and spends a lot of money. Restorative justice provides an alternative approach that actively seeks to repair the harm done to a community, a crime victim, and/or the victim’s family. Read more about restorative justice.)


The concept that knowing that someone else was punished for a crime will make another person less likely to commit the same crime. (Very low efficacy – this does not in fact work.)


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