California Code, Family Code - FAM § 8609.5

(a) The petitioner resides.

(b) The child was born or resides at the time of filing.

(c) An office of the agency that placed the child or is filing the petition for adoption is located.

(d) An office of the department or a public adoption agency that is investigating the petition is located.

(e) The county in which a placing birth parent or parents resided when the adoptive placement agreement, consent, or relinquishment was signed.

(f) The county in which a placing birth parent or parents resided when the petition was filed.

(g) The county in which the child was freed for adoption.