Search the Mercer County Inmate Population

The Mercer County Inmate Population

Nearly the whole Mercer County inmate population lives under one roof. The Mercer County Jail in Aledo is the only full detention facility in the county, and the Mercer County Sheriff's Office runs it. The sheriff's jail page says the building holds every sentenced and arrested county inmate, plus Cook County and federal inmates moving through or waiting for trial. The 2024 state inspection adds detainees held for the U.S. Marshals Service and for other Illinois and Iowa counties. So a one-day count is not only people arrested in Mercer County.

The numbers move for plain reasons. Arrests push the count up. Bond decisions, dismissals, and quick releases pull it down. A guilty plea or verdict can send a person to state prison, which moves them off the county books and onto the Illinois Department of Corrections rolls. Contract detainees held for other agencies come and go on their own schedule. Because of that mix, the size of the population on one date tells you less than the trend across several years.

Mercer County Inmate Population Statistics

The clearest sourced figures come from two places: the Mercer County Sheriff's jail page and the Illinois Department of Corrections jail inspection reports. The jail is rated for 102 beds, split 90 male and 12 female, per the IDOC compliance review dated March 5, 2024. On that inspection day the head count was 39. Mercer County itself is home to about 15,495 people, so the jail is small and rural by design.

State inspections are snapshots, not yearly averages. They still give the best public read on who was held and how full the jail was. The figures below pull straight from the IDOC reviews and the county census profile.

An annual average daily population and a yearly booking total were not published by the county, the sheriff, or IDOC in the sources reviewed. Those gaps are filled by a written records request, not by a guess.

Mercer County Inmate Population Trends

Three inspection counts span the recent period, and they sit close together. The jail held 44 people in June 2021, 41 in May 2022, and 39 in March 2024. Each count was below half of the 102-bed cap. That is a small, steady decline across snapshots, not proof of a falling trend, because the dates are scattered and the jail also takes contract detainees whose numbers shift.

For longer context, a 2013 correctional-population table from the Prison Policy Initiative listed 70 people at the Mercer County Jail on December 31 of that year. That older line sits well above the recent counts, but it predates the current period and should be read as history.

Note: Inspection counts are single-day snapshots and can rise on a busy court week, so treat them as official markers rather than the jail's true average.

Who Makes Up the Mercer County Inmate Population

The published breakdown is thin but useful. The 2024 inspection counted 35 men and 4 women. The 2022 count was 34 men and 7 women, and the 2021 count was 38 men and 6 women. That matches the bed split, which sets aside 90 beds for men and 12 for women. The capacity sheet lists zero juvenile beds, so the jail is not set up to hold youth long term.

• By sex - Men make up the large majority every inspection year, in line with the 90 male and 12 female bed split.
• Local vs. held for others - The count blends Mercer County arrests with Cook County, federal, and out-of-state detainees.
• Pre-trial vs. sentenced - The jail holds both arrested people awaiting court and those serving short county sentences.
• Juveniles - The capacity sheet shows no juvenile beds, and juvenile records are kept separate from adult records.

Race, age bands, and a pre-trial versus sentenced split were not published in the official Mercer County sources. A records request to the sheriff is the route to those details when a researcher needs them.

Mercer County Jail Capacity and Overcrowding

Capacity is the firmest number in this story. The current jail opened in 1989 with 30 beds. A later addition added 72 beds and brought the total to 102, and the building was last renovated in 2011. The space holds 47 double detention rooms and two four-bed dormitories. Every recent inspection count sat below half of that 102-bed limit, so the official record shows room to spare, not crowding.

A low one-day count does not mean the jail is quiet all year. Because Mercer holds detainees for the U.S. Marshals Service and for other counties, beds can fill and empty with arrangements that never touch a local arrest. The honest read on capacity is simple: the jail is built for 102 and was running well under that on the dates the state checked it.

Laws Governing the Mercer County Inmate Population

The data is public because Illinois law makes it public, and the jail is measured because the state sets standards. The Illinois Department of Corrections Jail and Detention Standards Unit collects jail population numbers monthly, keeps a database, inspects county jails each year, and forwards the figures to the Illinois Criminal Justice Information Authority. Open-records law lets the public ask for booking and arrest information that the jail keeps. A few statutes do the heavy lifting.

Those rules explain why the inspection PDFs exist and why a resident can request a booking record. The full Freedom of Information Act, at 5 ILCS 140, frames how to ask and what the sheriff may charge.

The Jail and Detention Standards Unit lays out its own authority and process in plain terms. A look at the state page shows how inspections, monthly reporting, and complaints fit together.

The state standards unit explains how Illinois oversees every county jail, including Mercer County's, on its official records page.

That overview is the backbone of the population figures cited above, since the same unit that writes the standards also counts the inmates and inspects the building.

Mercer County and the State Prison Population

Once a Mercer County case ends in a prison sentence, the person leaves the county count and joins the state count. The Illinois Department of Corrections runs the prisons for sentenced felons, and no IDOC prison sits inside Mercer County. That means the lookup path changes after sentencing. The jail phone answers questions about a current local inmate; the IDOC Individual in Custody Search answers questions about a sentenced state prisoner.

The state keeps a full facility list, and none of those prisons are in Mercer County. A quick scan of the IDOC list confirms where the state population is actually housed.

The takeaway is that a sentenced person from an Aledo courtroom will show up in the statewide locator after transfer, not on any Mercer County roster. The IDOC facilities list shows the prisons that hold the state share of the population.

How to Search the Mercer County Inmate Population

Mercer County does not publish an online jail roster. No current-inmate search, booking report, or mugshot gallery was found on the sheriff or county sites. That changes the search method: instead of typing a name into a roster, a person works a short chain of official channels. The jail phone stands in for the roster here, since it is the fastest way to confirm that someone is in custody right now.

1. Call the jail at (309) 582-5020 or (309) 582-5158 to confirm a current booking. This is the first and best step because no public roster exists.
2. Have the person's full legal name, date of birth, and the rough arrest date ready before you call.
3. Set up Illinois VINE at VINELink for custody and release alerts.
4. File a written FOIA request with the sheriff for a booking record or photo that is not online.
5. If the person was sentenced to prison, switch to the IDOC Individual in Custody Search instead of the jail.

The full how-to, with the records-request wording and the federal fallbacks, lives on the jail inmate records page.

Current Inmate Lookup in Mercer County

Because there is no roster screen, the lookup is really a choice between channels. Each one answers a slightly different question. The table below maps the question to the right office or tool so a search does not stall on the wrong one.

Victims have an extra path. The sheriff's crime-victim page explains how VINE and VINEmobile track a person through custody and send release notices, and it lists the identifiers a caller should have ready.

The county crime-victim page walks through VINE registration for anyone tracking a Mercer County inmate's custody status.

VINE will not replace the jail phone for a brand-new arrest, but it is the steadiest way to learn when custody changes after that first confirmation.

Past and Released Inmate Records

Finding a released or past inmate works differently than finding a current one. There is no archived booking feed to scroll, so the record comes from a request rather than a search box. Illinois open-records law, at 5 ILCS 140/2.15, requires criminal-justice agencies to release chronologically kept arrest information, which can include charges, the arresting agency, bond, and the dates a person was received, released, or transferred. A written FOIA to the sheriff is the way to reach those older records.

For someone who left the jail because of a prison sentence, the trail moves to the state. The IDOC locator and, after that, parole resources carry the record forward. For a person picked up by federal authorities, the federal locator takes over. The key is that the county jail only speaks to current local custody, so a past-inmate question almost always points to a records request or a different system.

What a Mercer County Inmate Record Shows

Even without a public profile screen, the inmate record itself is well defined. The state inspection checklist confirms what the Mercer County Jail keeps on each detainee, from identity and photographs to property, medical status, and court information. Not every field is public, but the list shows what a booking file holds and what a FOIA request can reach.

A booking record is not a conviction record. The charge written at intake can change once a prosecutor reviews the case, so the court file is the place to confirm the formal charge.

A few terms come up in almost every custody question, and knowing them speeds the search.

Pre-trial

The stage after arrest and before trial or plea, when the person is presumed innocent.

Detainee

A person held in jail, often awaiting court or held for another agency.

Detainer

A request from another agency, such as federal or immigration authorities, to keep holding a person.

Pretrial release

Court-ordered release under conditions rather than detention.

IDOC

The Illinois Department of Corrections, which holds sentenced state prisoners, not county detainees.

County Jail vs. State Prison: Where to Look

The most common search mistake is using the wrong system. The county jail and the state prison hold different parts of the population and answer to different offices. Pre-trial detainees and short-sentence inmates sit in the Mercer County Jail. Sentenced felons move to an Illinois Department of Corrections prison, which has its own locator. The comparison below keeps the two straight.

Federal and immigration custody add two more systems on top of these, which the next section covers.

State and Federal Inmate Search

Four locators cover the full range of custody tied to Mercer County. The state runs one, the federal government runs two, and immigration detention has its own. Each covers a different slice, so picking the right one matters more than searching hard.

• State prison - The IDOC Individual in Custody Search finds sentenced Illinois prisoners by last name, IDOC number, or birthdate.
• Federal prison - The Federal Bureau of Prisons locator covers people in federal custody from 1982 to today.
• Immigration - The ICE detainee locator searches by A-number or by name, country, and birthdate, and it does not list anyone under 18.
• Federal pre-trial - The U.S. Marshals Central District of Illinois handles federal defendants, who can sit in the Mercer County Jail while their case is federal.

That last point is a local quirk worth remembering. The 2024 inspection says the jail houses U.S. Marshals Service detainees, so a person can be physically in Aledo yet legally in federal custody. The jail inmate records page breaks down each locator's search fields.

Mercer County Detention Facilities

Mercer County has one detention facility, and every part of the local inmate population passes through it. The page for the jail covers visitation, mail, money, and the records process in full.

• Mercer County Jail - The county's only jail, holding pre-trial detainees, short-sentence inmates, and detainees held for federal and other-county agencies.

Mercer County Inmate Population FAQ

How big is the Mercer County inmate population?

State inspections counted 39 inmates in March 2024, 41 in May 2022, and 44 in June 2021. The jail is rated for 102 beds, so each of those counts ran below half capacity. Those are single-day snapshots from the Illinois Department of Corrections, not a yearly average, which the county does not publish.

How do I search the Mercer County inmate population?

There is no online roster. Call the jail at (309) 582-5020 or (309) 582-5158 to confirm a current inmate. Use Illinois VINE for release alerts, and file a sheriff FOIA request for a booking record. If the person was sentenced to prison, use the IDOC Individual in Custody Search instead.

Can I look up a released or past inmate?

Yes, but not through a search box. Past booking records come from a written FOIA request to the Mercer County Sheriff. If the person went to state prison, the IDOC locator carries the record. Federal custody moves to the Bureau of Prisons locator.

Is the jail overcrowded?

The official record shows room to spare. Every recent inspection count sat below half of the 102-bed capacity. The lone 2024 finding was a documentation gap on supervision checks, not crowding.

Why might the count include people from other places?

The jail holds detainees for the U.S. Marshals Service and for other Illinois and Iowa counties, along with Cook County and federal inmates in transit. A one-day count can include those outside holds, so it is not only Mercer County arrests.

Where do sentenced inmates go?

No state prison sits in Mercer County. After sentencing and transfer, a person appears in the statewide IDOC locator rather than on any county list. The county jail phone only answers for current local custody.