Reviewed and updated October 7, 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 on September 23, 2026.
Cook County, Illinois, has about 5.2 million 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 Cook 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, directory links and common questions.
Related guides: Cook County public records, Cook County warrants, Cook County inmate search, Cook County court records, Cook County police reports, Illinois arrest records and Illinois inmate search.
Criminal Cases in the Circuit Court of Cook County
A criminal case from Cook County is filed in the Circuit Court of Cook County, and the court file, kept by the Circuit Clerk, is the record of it that the public may see.
For Cook County, SearchSystems opened and checked the court records page for the county at cookcountyil.gov/service/court-records-and-archives (page title: Court Records and Archives), 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 Cook County
The Cook County Sheriff's Office and the agencies that report for Chicago, Cicero, Schaumburg, Evanston, Arlington Heights, Palatine and 112 more cities keep the arrest records in Cook 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 14 campus police departments and 15 other agencies in Cook County; each keeps the records of its own arrests.
The Elgin Police Department, the Buffalo Grove Police Department, the Deerfield Police Department and eight more are each listed by the FBI across several counties including Cook County, so their arrests are not broken out for Cook County here.
Together, the 100 agencies in Cook County with all twelve months of 2025 on file reported 71,187 arrests to the FBI that year; how each case ended is in the court file, not in the arresting agency's.
The Crimes Behind the Records: Cook County in 2025
The 98 agencies in Cook County with all twelve months of 2025 on file reported 15,071 violent and 110,656 property crimes to the FBI that year; the 91 of them with both 2025 and 2024 complete reported 121,768 crimes in 2025 against 140,360 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 Cook County public records guide.
The State's Attorney for Cook County
The State's Attorney decides which arrests in Cook County become charges and files them in the Circuit Court of Cook County; the office answers questions about pending prosecutions, and the case files themselves are court records.
The office's page SearchSystems verified is at cookcountyil.gov/agency/states-attorney (page title: States Attorney), phone (312) 603-1880, which answered when SearchSystems opened it on September 23, 2026.
The Sex Offender Registry for Cook County
Registered sex offenders living in Cook 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 Cook 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.
More Official Criminal Records Pages for Cook County
The SearchSystems directory, online since 1997, lists the official pages for Cook County and Illinois. These criminal records pages from its Cook County listing were opened again on October 1, 2026 and each one still answers:
- Detainee Discharge Tracker (iic.ccsheriff.org)
Frequently Asked Questions
Are criminal records public in Cook 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 Cook County criminal cases online?
The court records page SearchSystems verified for the county is at cookcountyil.gov (page title: Court Records and Archives).
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 Cook County?
The State's Attorney, reached at (312) 603-1880, which files its cases in the Circuit Court of Cook County.
Is this the official Cook 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.