Cal. PROB § 3921

Subject to the power of the court to transfer actions and proceedings as provided in the Code of Civil Procedure, a petition filed under this part shall be heard and proceedings thereon held in the superior court in the proper county, which shall be determined as follows: (a) If the minor resides in this state, in either of the following counties: (1) Where the minor resides. (2) Where the custodian resides. (b) If the minor does not reside within this state, in any of the following counties: (1) Where the transferor resides. (2) Where the custodian resides. (3) Where the estate of a deceased or legally incapacitated custodian is being administered. (4) Where a parent of the minor resides. (c) If neither the minor, nor the transferor, nor any parent resides within this state, and no estate of a deceased or legally incapacitated custodian is being administered within this state, in any county.