The last county where the couple lived together, with a common intent to remain married.
The term the court uses to describe the correct county to file a case is “venue.”
The parties may consent venue, if the court has subject matter jurisdiction for the divorce. So, if both parties agree, a divorce case may be filed in a different county. For example, a divorcing couple might agree to file in an adjacent county for privacy reasons. However, if the responding party objects, the case will be moved from the “wrong” county back to the county where the couple last lived together.
Or as the court puts it, “The law is well settled in Florida that a cause of action for a dissolution of marriage arises in the Florida County in which both parties last resided with a common intent to remain married.”
In addition to filing the case in the correct venue, the court also needs “subject matter jurisdiction” to enter the divorce, and “personal jurisdiction” over the opposing party. The subject of jurisdiction is complex, and beyond the scope of this FAQ