The judiciary of Illinois is the unified court system of Illinois responsible for applying the Constitution and law of Illinois. It consists of the Supreme Court, the Appellate Court, and circuit courts. The Supreme Court oversees the administration of the court system.
Courts
Circuit courts
The Illinois circuit courts are trial courts of original jurisdiction. There are 24 judicial circuits in the state, each comprising one or more of Illinois' 102 counties. Six circuits comprise solely of a single county; these are Cook, Kane, Will, DuPage, Lake, and McHenry. The other 18 circuits each contain between two and 12 counties.
The circuit court has general jurisdiction and can decide, with few exceptions, any kind of case. The exceptions are redistricting of the Illinois General Assembly and the ability of the governor of Illinois to serve or resume office. The circuit court also shares jurisdiction with the Supreme Court of Illinois to hear cases relating to revenue, mandamus, prohibition, and habeas corpus. However, if the supreme court chooses to exercise its jurisdiction over these cases, the circuit court may not decide them. The circuit court also reviews administrative decisions of certain state agencies.
There are two kinds of judges in the circuit court: circuit judges and associate judges. An associate judge can hear any case, except criminal cases punishable by a prison term of one year or more, unless the associate judge has received approval from the Supreme Court to hear other criminal cases.
Appellate Court
The Illinois Appellate Court is the court of first appeal for civil and criminal cases rising in the Illinois circuit courts.
Three Illinois Appellate Court judges hear each case and the concurrence of two is necessary to render a decision. The Illinois Appellate Court will render its opinion in writing, in the form of a published opinion or an unpublished order. As of 1935, decisions of the Illinois Appellate Court became binding authority upon lower courts in Illinois.
The Illinois Appellate Court has fifty-four judges serving five districts, administratively centering on Chicago (1st District), Elgin (2nd District), Ottawa (3rd District), Springfield (4th District), and Mt. Vernon (5th District).
Civil cases appealed from the Illinois Appellate Court are heard by the Supreme Court of Illinois upon the grant of a Petition for Leave to Appeal under Illinois Supreme Court Rule 315, a Certificate of Importance under Illinois Supreme Court Rule 316, or a Petition for Appeal as a Matter of Right under Illinois Supreme Court Rule 317. The same rules apply to criminal cases.
Supreme Court
The Supreme Court of Illinois is the state supreme court and consists of seven justices including a chief justice.
The court has limited original jurisdiction and has final appellate jurisdiction. Prior to the state's moratorium and abolition of the death penalty (see capital punishment in Illinois), the court had mandatory jurisdiction in capital cases and cases where the constitutionality of laws has been called into question as well as had discretionary jurisdiction from the Illinois Appellate Court.
Other tribunals
The Illinois Court of Claims decides all monetary claims against the government and is better characterized as part of the legislative branch.
Administration
The Supreme Court oversees the administration of the court system. Along with the state legislature, the court promulgates rules for all state courts.
The Administrative Office of the Illinois Courts (AOIC) assists the Supreme Court in administration, and is headed by the Administrative Director. The AOIC conducts the election process for the appointment of associate judges; provides support services to the courts and the judicial conference; develops the judicial budget; provides legislative support services to the courts; assists in the development and oversight of the judicial education plan; develops and monitors probation programs for the circuit courts and administrative-service training for all judges; collects and publishes statistical information on caseloads; and handles payroll for all judicial personnel. The Administrative Director also is secretary of the Illinois Courts Commission, and is an ex officio member of the Illinois Judicial Conference. The AOIC Executive Office plans and directs AOIC staff support for Supreme Court Committees and the Committees of the Illinois Judicial Conference.