“‘Venue’ refers to the proper county for trial of the action among courts which otherwise have jurisdiction to proceed. Proper venue in a marital action is not a ‘jurisdictional’ requirement. Thus, an action may proceed to trial and judgment though filed in the ‘improper’ county unless the opposing party makes a timely objection. On the other hand, when improper venue is timely challenged, the court where the action was commenced is compelled to transfer the matter to the county of proper venue. On timely motion, various statutes authorize a discretionary transfer from the county of proper venue to another county. Broadly, the ground for a discretionary transfer is the “convenience of witnesses” and the “ends of justice.” However, marriage dissolution and postjudgment family law actions are subject to special discretionary transfer rules.
[California Practice Guide-Family Law [citations to primary sources omitted]]