Family Code 2320 states, “A judgment of dissolution of marriage may not be entered unless one of the parties to the marriage has been a resident of this state for six months and of the county in which the proceeding is filed for three months next preceding the filing of the petition.

Family Code 2320 applies to dissolutions only. For legal separations you can file in any county where at least one of the parties resides.

If you were served with a summons and you feel that the venue (court where disso was filed) is not proper you can file a motion to quash the proceeding or a motion to change venue.