The proper venue for an action to modify child custody rights, including physical custody as well as legal custody, is an issue that is controlled by statute in Georgia, under the Intrastate Jurisdiction Act.
OCGA Section 19-9-23 [Action to Change Legal Custody] reads as follows:
“(a) Except as otherwise provided in this Code section, after a court has determined who is to be the legal custodian of a child, any complaint seeking to obtain a change of legal custody of the child shall be brought as a separate action in the county of residence of the legal custodian of the child.
(b) A complaint by the legal custodian seeking a change of legal custody or visitation rights shall be brought as a separate action in compliance with Article VI, Section II, Paragraph VI of the Constitution of this state.
(c) No complaint specified in subsection (a) or (b) of this Code section shall be made:
(1) As a counterclaim or in any other manner in response to a petition for a writ of habeas corpus seeking to enforce a child custody order; or
(2) In response to any other action or motion seeking to enforce a child custody order.
(d) The use of a complaint in the nature of habeas corpus seeking a change of child custody is prohibited.” (emphasis supplied)
The issue of which party is the “legal custodian” of the child is controlled by reference to the custody agreement (or existing law, where such is unavailable) which should designate the party that is responsible.