The Wisconsin circuit courts are the state's trial courts. Circuit courts have original jurisdiction in all civil and criminal matters within the state, including probate, juvenile, and traffic matters, as well as civil and criminal jury trials.
Clerks of circuit court are independently elected, constitutional officers who work in close cooperation with the chief judges, district court administrators, and staff of the Director of State Courts Office. The clerks provide management and administrative leadership in each circuit and are indispensable to the effective functioning of Wisconsin's circuit courts.
Prior to April 5, 1977, there were two levels of trial courts in Wisconsin: the county courts and the circuit courts. Although the workload split varied from county to county, in general the judges in the county courts handled probate, juvenile, and traffic matters, and the judges in the circuit courts handled civil and criminal jury trials.
The reorganization created a single-level, unified trial court that handles all types of cases.