65 ILCS 5/11-80-19

The corporate authorities of each municipality may name originally and then may change the name of any street, avenue, alley, or other public place. No change in the name of any street, avenue, alley or other public place shall be effective until 30 days after the election authorities having jurisdiction in the area in which the name of the public place is changed and the post office branch serving that area have been notified by the corporate authority initiating such action of the change in writing by certified or registered mail.