Reviewed and updated October 9, 2026 by the SearchSystems.net editorial team. The arrest and crime counts are the ones each agency reported to the FBI, as the FBI held them on October 8, 2026. Every office link was opened and checked against the office's own site between September 23, 2026 and October 4, 2026.
Williamson County, Illinois, has about 67,000 residents (2024 Census Bureau estimate). In Illinois the public criminal record is the court file, kept by the Circuit Clerk; the statewide criminal history kept by the Illinois State Police is open to anyone who asks. This guide says where each record of a criminal case from Williamson County is kept and how it is seen.
This guide covers the court file, the statewide record, local arrest records, the crimes behind the records, the prosecutor, sex offender registry, records requests and common questions.
Related guides: Williamson County public records, Williamson County arrest records, Williamson County warrants, Williamson County inmate search, Williamson County court records, Illinois arrest records and Illinois inmate search.
Criminal Cases in the Circuit Court of Williamson County
A criminal case from Williamson County is filed in the Circuit Court of Williamson County, and the court file, kept by the Circuit Clerk, is the record of it that the public may see.
For Williamson County, SearchSystems opened and checked the court records page for the county at williamsoncountyil.gov/departments/circuit-clerk (page title: Circuit Clerk | Williamson County), phone (618) 997-1301, Monday-Friday 8:00 a.m. - 4:00 p.m., which answered when SearchSystems opened it on September 23, 2026.
Illinois has no single public index of every trial court case; each court's records are looked up through that court.
The Illinois Criminal History and Your Own Copy
Illinois is one of the states that lets anyone look up another person's statewide criminal history: conviction information is public under the Uniform Conviction Information Act, through the Illinois State Police. The result is the repository record, what agencies reported to the state, which is wider than one county's court index but can lag it.
To see your own record, the route is a name-based or fingerprint-based request to the Illinois State Police. The state page SearchSystems verified for it is at isp.illinois.gov/BureauOfIdentification/MyRecord.
Arrest Records Kept Locally in Williamson County
The Williamson County Sheriff's Office and the agencies that report for Marion, Herrin, Carterville, Johnston City, Cambria, Energy and one more cities keep the arrest records in Williamson County: the report and the booking record of each arrest stay with the agency that made it, separate from the court file and from the state repository.
The FBI's agency list also places one more agency in Williamson County: John A. Logan College (campus police); it keeps the records of its own arrests.
Together, the five agencies in Williamson County with all twelve months of 2025 on file reported 2,793 arrests to the FBI that year; how each case ended is in the court file, not in the arresting agency's.
The agencies and their counts, year by year, are in Williamson County arrest records.
The Crimes Behind the Records: Williamson County in 2025
The four agencies in Williamson County with all twelve months of 2025 on file reported 124 violent and 717 property crimes to the FBI that year; the two of them with both 2025 and 2024 complete reported 830 crimes in 2025 against 939 in 2024. Each reported crime is a report on file with the agency that took it, and each arrest that follows is the start of a criminal record.
The full crime section, agency by agency, is on the Williamson County public records guide.
The State's Attorney for Williamson County
Charges in Williamson County are filed by the State's Attorney, which reviews the arrests of every agency in the county and brings the cases in the Circuit Court of Williamson County.
The office's page SearchSystems verified is at williamsoncountyil.gov/states-attorney (page title: State's Attorney | Williamson County), phone (618) 998-2229, which answered when SearchSystems opened it on September 23, 2026.
The Sex Offender Registry for Williamson County
Registered sex offenders living in Williamson County are listed on the Illinois Sex Offender Registry, run by the Illinois State Police at illinois.gov. The registry is public and can be searched online.
Registration itself is done in person with the local agency where the registrant lives: the sheriff's office, or the city police in a city with its own department.
Asking an Agency in Williamson County for a Record
An arrest report, a booking record or a local criminal history letter comes from the agency that holds it, not from the court.
Under the Illinois Freedom of Information Act a county office must answer a request within 5 business days, with one 5-day extension, and it may charge copying only after the first 50 pages.
Frequently Asked Questions
Are criminal records public in Williamson County?
The court files of criminal cases are public, and so is the statewide criminal history kept by the Illinois State Police: conviction information is public under the Uniform Conviction Information Act. The arrest report itself is released by the agency that made the arrest, under the Illinois Freedom of Information Act.
Can I search Williamson County criminal cases online?
The court records page SearchSystems verified for the county is at williamsoncountyil.gov (page title: Circuit Clerk | Williamson County).
How do I get my own Illinois criminal history?
Through a name-based or fingerprint-based request to the Illinois State Police.
Who prosecutes crimes in Williamson County?
The State's Attorney, reached at (618) 998-2229, which files its cases in the Circuit Court of Williamson County.
Is this the official Williamson County website?
No. SearchSystems.net is an independent public records guide, online since 1997. It links to the official county, court and state offices described above and does not hold records, charge for them or take requests.