65 ILCS 5/2-4-6

If a change of name is made, the corporate authorities shall file a copy of the order making the change with the Secretary of State. The Secretary of State shall publish a notice of the change at least once in one or more newspapers published in the municipality, or, if no newspaper is published therein, then in one or more newspapers with a general circulation within the municipality. In municipalities with less than 500 population in which no newspaper is published, publication may instead be made by posting a notice in 3 prominent places within the municipality. The courts shall take judicial notice of the change of name.