750 ILCS 46/604: Venue.

(a) Venue for a proceeding to adjudicate parentage is any county of this State in which a party resides, or if the presumed parent or alleged genetic parent is deceased, in which a proceeding for probate or administration of the presumed parent's or alleged genetic parent's estate has been commenced, or could be commenced.

(b) A proceeding for the allocation of parental responsibilities is commenced in the county where the child resides.

(c) A parentage proceeding under the Gestational Surrogacy Act or Article 7 of this Act may be commenced in any county in this State.