California Code, Code of Civil Procedure - CCP § 392

(a) Subject to the power of the court to transfer actions and proceedings as provided in this title, the superior court in the county where the real property that is the subject of the action, or some part thereof, is situated, is the proper court for the trial of the following actions:

(b) In the court designated as the proper court in subdivision (a), the proper court location for trial of a proceeding for an unlawful detainer, as defined in Section 1161, is the location where the court tries that type of proceeding that is nearest or most accessible to where the real property that is the subject of the action, or some part thereof, is situated. Otherwise any location of the superior court designated as the proper court in subdivision (a) is a proper court location for the trial. The court may specify by local rule the nearest or most accessible court location where the court tries that type of case.