The Circuit Court of Cook County of the State of Illinois is the largest of the 24 judicial circuits in Illinois and one of the largest unified court systems in the world. It has about 400 judges who serve the 5.2 million residents of Cook County within the City of Chicago and its 126 surrounding suburbs. More than 1 million cases are filed each year.

The Circuit Court of Cook County was created by a 1964 amendment to the Illinois Constitution which reorganized the courts in Illinois.  The amendment effectively merged the often confusing and overlapping jurisdictions of Cook County’s previous 161 courts into one uniform and cohesive court of general jurisdiction.

Today, the Circuit Court of Cook County is a unified court system in which all trial courts are consolidated under the chief judge, Honorable Timothy C. Evans, who has centralized authority to coordinate and supervise the administrative functions of the court.

Chief Judge Evans is responsible for the assignment of approximately 400 judges throughout the court's ten divisions and six geographic districts and the appointment of a presiding judge to head  each division and district.  The Chief Judge also oversees the court’s Surety Section and the Juvenile Justice and Child Protection Resource Section, appointing a judge to head each of those sections as well.

The Office of the Chief Judge is the administrative arm of the court.  It prepares the court's annual budget and supervises approximately 2,600 non-judicial employees who work in 15 offices that provide probation and other court-support services, including court reporting and foreign language interpreting. 

For administrative and management purposes, the court has divided Cook County into six geographic subdistricts.  This allows the court to better serve the county’s large population. 

The Circuit Court's six districts and the areas which they serve are: