jail411

Practical guide

Jail vs Prison: What's the Difference?

Published March 6, 2026

Confirm the current facility before you act.
Custody, providers, addresses, prices, and rules can change. Use the operating agency’s official instructions for the person and location involved.
Who runs which facility, and who to contact Five custody systems and the agency that operates each: county or city jail, operated by the county sheriff or in some cities the city police department, contact for booking status, bail, and that jail's own visitation and phone rules; state prison, operated by the state department of corrections, contact for transfers, classification, and statewide visitation or mail policy; federal facilities, operated by the Federal Bureau of Prisons, contact for the federal inmate locator, unit team, and federal visiting rules; ICE detention, operated by ICE, often through contracted county jails or private facilities, contact for the ICE Online Detainee Locator, an immigration attorney, or the local ICE field office; and juvenile facilities, operated by the state or county juvenile justice agency, contact for the juvenile court and the assigned caseworker, since most juvenile records are confidential. Some states operate unified systems where one agency runs more than one of these. Who runs which facility, and who to contact Five systems, five different operating agencies. Confirm which one applies before you call. County or city jail OPERATED BY The county sheriff, or in some cities the city police department. CONTACT FOR Booking status, bail, and that jail’s own visitation and phone rules. State prison OPERATED BY The state department of corrections. CONTACT FOR Transfers, classification, and statewide visitation or mail policy. Federal (BOP) OPERATED BY The Federal Bureau of Prisons. CONTACT FOR The federal inmate locator, unit team, and federal visiting rules. ICE detention OPERATED BY ICE, often through contracted county jails or private facilities. CONTACT FOR The ICE Online Detainee Locator, an immigration attorney, or the local ICE field office. Juvenile facility OPERATED BY The state or county juvenile justice agency. CONTACT FOR The juvenile court and the assigned caseworker — most records are confidential. Some states run unified systems where one agency operates more than one of these. Confirm the operator shown in the directory, then use that agency’s current instructions.
The right agency to call depends on which system is holding the person, not on what the facility calls itself. See the exceptions below for unified state systems.

The short answer

Jails are usually run by counties or cities and primarily hold people awaiting trial or serving shorter local sentences. Prisons are usually run by state or federal agencies and primarily hold people serving longer sentences after conviction.

Why the distinction matters

The correct system determines which inmate locator, visitation rules, phone provider, mail address, and release process applies. A person may move from a police holding cell to a county jail, then later to a state or federal prison.

Important exceptions

Several states operate unified correctional systems, and names such as detention center, correctional facility, or state jail do not always reveal who runs a site. Use the operator and jurisdiction shown in the directory, then confirm current placement with the official agency.