The Wisconsin circuit courts were established by of the Constitution of Wisconsin, ratified May 8, 1848. There were originally five numbered circuit courts—each with one judge. In the first version of the constitution, and until 1853, the circuit court judges also served as the Wisconsin Supreme Court. The number of circuits was expanded via legislation as the population of the state grew, growing to 26 numbered circuits by 1965.
The modern circuit court system was established in 1977, when the Wisconsin Legislature enacted . The court reorganization was enabled by an amendment to the state constitution earlier that year. Act 187 combined the existing circuit court and county court systems to create a single level of trial courts. There are now 69 circuit courts in the state with 261 current judges. The circuit courts are organized into nine judicial administrative districts.