County Jail, State Prison, or Federal? How to Tell Where Your Loved One Is Held

01Quick Answer: The Four Systems, at a Glance

Most people in custody in the United States are held in one of four systems, and knowing which one your loved one is in tells you where to search, whom to call, and how you can contact them. The short version: county jails are run by the local sheriff and hold people whose cases are still moving through the local courts; state prisons hold people already sentenced for state crimes; the federal Bureau of Prisons holds people sentenced in federal court; and ICE runs a separate immigration detention system that is civil, not criminal.

You are not looking for one master list. You are figuring out which of four systems your person is in — and each has its own front door.

The four systems in one glance

• County jail — run by the county sheriff. Holds people awaiting trial, people on short sentences, and people being held for other agencies. Search the county’s online jail roster (“Who’s in Jail,” inmate search, or custody lookup).
• State prison — run by the state Department of Corrections (DOC). Holds people convicted of state felonies, usually serving more than a year. Search that state’s DOC inmate or “offender” locator.
• Federal custody — the Federal Bureau of Prisons (BOP) holds people sentenced in federal court; before sentencing, the U.S. Marshals Service often holds people, frequently in a contracted county jail. Search the Federal Bureau of Prisons Inmate Locator.
• Immigration (ICE) detention — a separate, civil federal system for immigration matters. Search the ICE Online Detainee Locator System using the person’s A-Number or their name, country of birth, and date of birth.

If you only remember one thing, let it be this: the system a person is in can change over the first days and weeks, and that is normal. This guide gives you a reliable way to tell which system you are looking at right now, so you are never just guessing.

02Why the Distinction Changes Everything

It can feel like a technicality — jail, prison, detention, does the label really matter when someone you love is locked up? It matters enormously, because each system is a separate government with its own building, its own computer records, its own phone and money providers, and its own rules for visits and mail. Searching the wrong system is like calling the wrong country’s directory: you can dial all night and never find them, not because they are lost, but because you are looking in the wrong place.

The distinction also shapes the practical questions you care about most: how you set up a phone account, how you put money on their books, how and when you can visit, and how you follow their court case. A county jail visit is nothing like a state prison visit. Money added at one facility does not follow a person to a different system. Court dates in a federal case are tracked in a completely different place than a county case.

What the system tells you

• Where to search — a county roster, a state DOC locator, the federal BOP locator, or the ICE detainee locator. Searching the right one is often the difference between an answer in minutes and a night of dread.
• Who has authority — the county sheriff, a state agency, the federal government, or immigration authorities. That determines whom you call and who can actually answer your questions.
• How you contact them — each system contracts with its own official phone, video, and commissary providers, and the verified steps differ from one to the next.
• Where the case lives — local court, state court, federal court, or immigration court. Each has its own records and its own way of announcing hearing dates.

The label is not bureaucratic trivia. It is the map. Get the system right, and everything else finally has an address.

03County Jail: The Sheriff’s Front Door

The county jail is where the overwhelming majority of people go first, and it is where most people stay while a case is pending. In most parts of the country, the county jail is run by the elected sheriff, though some large cities run their own jail systems under a different department. It is a local operation, funded and staffed at the county level, and it is almost always your starting point.

Who is held in a county jail

County jails hold a mix of people at different stages, which is part of why they can be confusing:

• People who were recently arrested and are awaiting a first court appearance or a bail decision.
• People whose cases are still moving through the local courts and who have not been able to post bail or were not granted release.
• People serving shorter sentences — commonly for misdemeanors or lower-level offenses, though the exact limits vary by state.
• People being held for another agency under a hold or detainer — for a nearby county, the state, the U.S. Marshals, or immigration authorities. This is why someone can physically be in a county jail while another government has an interest in them.

Because the county is where so many paths begin and end, it is your anchor. If you do not know which system your loved one is in, start with the county jail where the arrest happened. Even when the answer turns out to be “they were transferred,” the county is usually the place that can tell you where.

How to search a county jail

Most county jails publish an online roster — sometimes called “Who’s in Jail,” an inmate search, or a custody lookup. Search by last name first, remember that a fresh arrest may not appear for several hours until booking is complete, and note the booking number when you find it. If the roster is lagging or hard to use, call the jail’s non-emergency or intake line rather than 911.

04State Prison: The State Department of Corrections

State prison is a different world from county jail, run by a statewide agency usually called the Department of Corrections, or DOC (some states use names like Department of Corrections and Rehabilitation, or Department of Public Safety). People are held in state prison after they have been convicted and sentenced for a state crime — the process has moved past the local courts, and the person is now in the custody of the state, not the county.

How state prison differs from county jail

• Timing — people generally arrive in state prison after sentencing, not right after an arrest. Before that, they are usually in a county jail.
• Length — state prison is typically for longer sentences, often more than a year, though this varies by state and by the specific case.
• Location — a person may be housed in a state facility far from home, and the state may move people between prisons for classification, programming, medical care, or bed space.
• Records — the person is now tracked in the state system under a state DOC number, not the county booking number you may have started with.

How to search a state prison system

Every state runs its own inmate locator, often labeled an “inmate search,” “offender search,” or “inmate locator” on the Department of Corrections website. These usually let you search by name and by the state-assigned number if you have it. A few things to keep in mind:

1. Search the DOC website for the state where the person was convicted — not necessarily the state where you live or where the arrest happened, if those differ.
2. Try the last name alone first, then add first name or birth year if there are many matches.
3. Look for the person’s DOC or inmate number and write it down; you will use it for mail, phone setup, and visitation.
4. Note the facility name and check that state’s rules for that specific prison, since visiting and mail procedures differ between institutions even within one state.

If you recently found your loved one in a county jail and then they seem to vanish from that roster, one common explanation is that they were transferred into state prison after sentencing. When that happens, stop searching the county system and switch to the state DOC locator.

05Federal Custody: The Bureau of Prisons and the U.S. Marshals

Federal custody is an entirely separate track from anything at the county or state level. It applies to people charged with or convicted of federal crimes — cases prosecuted in federal court by the U.S. government rather than a local district attorney or state prosecutor. Two federal agencies matter most to families here, and telling them apart helps you know where to search.

Two stages, two agencies

• Before sentencing — the U.S. Marshals Service is generally responsible for people in federal pretrial custody. The Marshals often do not run their own long-term jails; instead they house people in contracted county jails or private facilities, which is why a person in “federal custody” can physically be sitting in a local county jail.
• After sentencing — the Federal Bureau of Prisons (BOP) takes custody of people sentenced to federal prison and assigns them to a federal institution, which can be anywhere in the country.

How to search federal custody

The primary tool is the Federal Bureau of Prisons Inmate Locator, a nationwide search on the BOP website. It covers people currently in BOP custody and, for many, historical records as well. You can search by the person’s federal register number if you have it, or by name along with details like age or race to narrow the results.

One important limitation: the BOP locator does not always show people who are still in pretrial custody under the U.S. Marshals and have not yet entered the Bureau of Prisons. If you believe the case is federal but the BOP locator turns up nothing, the person may still be held pre-sentencing in a contracted county jail. In that situation, the county jail roster and the federal court record can help you confirm where they are.

06ICE Immigration Detention: A Separate, Civil System

Immigration detention is run by U.S. Immigration and Customs Enforcement, or ICE, and it is important to understand that it is a civil system, not a criminal one. A person can be held by ICE without being charged with any crime; immigration detention is tied to a person’s immigration case, not a criminal sentence. This is a distinct federal system, separate from the Bureau of Prisons, with its own locator and its own rules.

Where ICE holds people

ICE detains people in a patchwork of locations: dedicated ICE detention centers, privately operated facilities, and county jails that contract with ICE to hold immigration detainees. This is why a family can be told their loved one is “with immigration” while the physical building is a local county jail. It is also why an immigration “detainer” placed on someone in a county jail can be so confusing — it is a request from ICE asking the jail to notify them before releasing the person.

How to search for someone in ICE custody

ICE operates the Online Detainee Locator System, a public search on the ICE website. There are generally two ways to search it:

1. By A-Number — the person’s Alien Registration Number, a unique identifier that begins with the letter “A” followed by a series of digits, entered together with the person’s country of birth.
2. By biographical information — the person’s first and last name, country of birth, and date of birth, entered exactly. Small differences in spelling or name order can cause a search to come up empty.

Immigration situations carry real legal stakes, and the right next step depends entirely on the specifics of a person’s case. This guide cannot give legal advice. If ICE or an immigration detainer is involved, it is often wise to speak with an immigration attorney or a trusted legal aid organization before making decisions, and to be thoughtful about whom you share personal details with.

07How to Tell Which System You Are Looking At

When you do not yet know which system holds your loved one, you can usually reason your way to the answer by working from a few clues. None of these is a guarantee, but together they point you in the right direction fast.

Clues that narrow it down

• Who made the arrest — city or county officers usually mean the person starts in a county jail. Federal agents point toward federal custody. An immigration enforcement action points toward ICE.
• How far along the case is — someone recently arrested and awaiting court is almost always in a county jail. Someone already convicted and sentenced for a state crime is likely in state prison.
• What court is involved — a local or state court points to county or state custody; a federal court points to federal custody; an immigration court points to ICE.
• Which words you are hearing — phrases like “DOC number,” “register number,” “A-Number,” or “detainer” are strong hints about which system is involved.

A simple order to search

When in doubt, search in this order, and stop as soon as you find your person:

1. Start with the county jail roster for the county where the arrest happened — this catches the large majority of recent arrests.
2. If the case has reached sentencing for a state crime, check that state’s Department of Corrections locator.
3. If you believe the charges are federal, search the Federal Bureau of Prisons Inmate Locator — and if it is empty, consider that the person may be in pretrial custody under the U.S. Marshals in a county jail.
4. If immigration is involved in any way, search the ICE Online Detainee Locator System by A-Number or by name, country of birth, and date of birth.

You rarely need to know the answer before you start. You need to start, follow the clues, and let each result tell you where to look next.

08The Locators, Side by Side

Because each system uses a different search tool with a different name, it helps to see them together. Keep this as a quick reference while you search.

• County jail → the county’s online jail roster, often called “Who’s in Jail,” an inmate search, or a custody lookup, run by the sheriff or county. Best searched by last name; a fresh booking may take hours to appear.
• State prison → the state Department of Corrections inmate or “offender” locator, one per state, searchable by name and by the state DOC number.
• Federal prison → the Federal Bureau of Prisons Inmate Locator, a single nationwide search, by federal register number or by name and identifying details.
• ICE detention → the ICE Online Detainee Locator System, searchable by A-Number with country of birth, or by full name, country of birth, and date of birth.

A recurring frustration is that these are four separate front doors that do not talk to each other. A single name may need to be typed into several of them before you find a match, especially early on when you are not yet sure which system applies. That is normal, and it is not a sign that anything has gone wrong.

09How People Move Between Systems

One of the most disorienting things for families is that a person does not necessarily stay in one system. Custody can hand off from one government to another, and each handoff can make someone briefly “disappear” from the locator you were watching. Understanding the common paths takes the fear out of it.

Common ways custody moves

• County jail to state prison — after a person is convicted and sentenced for a state felony, they are typically transferred from the county jail into the state Department of Corrections. At that point they leave the county roster and appear in the state locator.
• County jail to federal custody, or the reverse — in a federal case, the U.S. Marshals may hold someone in a county jail before sentencing, then the Bureau of Prisons takes over afterward. A person can move between a local building and the federal system depending on the stage of the case.
• Between counties or states — a hold or detainer from another jurisdiction can lead to a transfer once the local matter is resolved.
• Into or out of ICE custody — an immigration detainer can lead to a person being transferred to ICE after a local case ends, and ICE may move people between detention facilities.

Each move can reset practical things you had set up — phone access, mail routing, and any money on the person’s account — because different systems and facilities use different official providers. When someone moves, re-verify the current facility and its official phone and commissary providers before sending anything, and update your notes with the new ID number the receiving system assigns.

A person vanishing from one locator is usually not a crisis. It usually means custody moved, and the answer is now waiting in a different system.

10How Contact and Money Differ by System

Once you know which system holds your loved one, the next questions are almost always the same: how do I talk to them, how do I visit, and how do I put money on their account? The answers differ sharply from one system to the next, and even between facilities within the same system, so the safe habit is to confirm the rules for the exact building where the person is held.

What tends to vary

• Phone and video — each facility contracts with specific official providers, and you usually set up and fund an account through that provider. County, state, federal, and ICE facilities often use different companies with different steps.
• Visitation — county jails frequently rely on short in-person or video visits with limited hours; state and federal prisons often have scheduled visiting days with their own approval processes; ICE facilities have their own visitation rules. Always check the specific facility.
• Money on the books — the verified way to add commissary or phone funds depends on the facility’s official provider. Money added at one facility does not automatically follow a person to a new one after a transfer.
• Mail — addressing rules, what is allowed, and whether mail is scanned or forwarded vary widely by system and facility, and can change.

Because these details change and because unofficial third parties sometimes advertise services that are not the facility’s real provider, always start from the official source — the facility’s or agency’s own information — before you send money or set up an account. Getting the system and the building right first is what makes everything after it work.

Confirm the exact facility before you send a dollar. In this world, the right provider is always the one the facility itself names.

11Staying Steady While You Sort It Out

Untangling which system your loved one is in is real work, done while you are frightened and tired, and it is normal to feel overwhelmed by the sheer number of agencies and websites and phone trees. Be patient with yourself. You are learning a system that is genuinely fragmented, and confusion is a reasonable response to a confusing thing, not a failure on your part.

Gentle reminders for the search

• Work one system at a time. Confirm or rule out the county before you spiral into every possibility at once.
• Write down every ID number as you find it — booking number, DOC number, federal register number, A-Number — because each one is a key that unlocks the right locator.
• Eat something, drink water, and let one trusted person sit with you while you make calls. Steadiness helps more than speed here.
• Treat this guide as a starting map, not the final word. Custody, facility, and providers must be confirmed directly with the agency, jail, or a qualified attorney.

Finding out which system holds your loved one is a genuine accomplishment, even though it may feel like only the first step. Once you know whether you are dealing with a county, a state, the federal government, or immigration, the fog lifts a little: you know which locator to trust, which number to call, and which rules apply. From there, the steadier work of staying connected can begin.

You do not have to master four systems tonight. You only have to figure out which one, and then take the next honest step inside it.

Because rules differ so much by facility, county, and state — and because federal and immigration matters carry their own separate rules — treat everything here as general guidance. Always confirm the specifics directly with the agency, the facility, or, when the stakes are legal, a qualified attorney. And when the not-knowing feels heaviest, come back to this: your person is in one of these systems, that system can be identified, and you are already doing the work to find them.