Prior to June 1998, California's trial courts consisted of Superior and Municipal courts, each with its own jurisdiction and with its number of judges fixed by the Legislature; prior to 1951, twelve inferior courts with municipal or judicial township jurisdiction were designated by the Board of Supervisors to try civil and lesser criminal cases in the County. The County Court (also known as the Sonoma County Justice Court; more formally designated as the State of California's County Court for Sonoma County), served as referees for the Juvenile Court, among other duties involving minor offenses. The County Court was reorganized in 1952 as part of the State of California's inferior court reorganization program authorized by the voters as California Proposition 3 in 1950, which combined the offices of the municipal and township justices of the peace and city police court judges; the Santa Rosa Justice Court and other, local municipal courts were combined as the Santa Rosa Judicial District Court, or more formally, the State of California's Municipal Court for the Santa Rosa Judicial District on Jan. 1, 1952. The Santa Rosa Judicial District aborbed the Cotati-Rohnert Park area in 1964 and changed names to the Sonoma County Central Judicial District in 1965 when it was consolidated with the Redwood Judicial District, with the Court referred to as the Municipal Court for the Sonoma County Central District). The name later changed again to the Sonoma County Judicial District. The Northern Sonoma County Judicial District was consolidated with the Sonoma County Judicial District in 1971

A number of other reorganizations and consolidations of the County's District Courts took place over the next two decades until the District Courts and other inferior courts were absorbed into the Superior Court following another voter-authorized reorganization in 1998, California Proposition 220.