Circuit Court of Cook County

The Circuit Court of Cook County is the largest of the 24 circuit courts in the judiciary of Illinois as well as one of the largest unified court systems in the United States – second only in size to the Superior Court of Los Angeles County since that court merged with other courts in 1998.

The modern Cook County Circuit Court was created through a 1964 amendment to the Illinois Constitution which reorganized the courts of Illinois. The amendment effectively merged the often confusing and overlapping jurisdictions of Cook County's 161 courts, which were organized as municipal courts and specialized courts, into one uniform and cohesive court of general jurisdiction, organized into divisions, under the administration of one chief judge.

Source: Wikipedia