In the event the voters approve of a merger of 2 or more cities, or villages, or incorporated towns or townships and the merger affects one or more public libraries the library taxes levied before such merger, shall continue to be levied and collected for library purposes. The ceiling on the annual tax for the maintenance of the public library resulting from the merger shall be at a rate not higher than any lawful rate authorized to be extended before the merger in any of the merged areas.
75 ILCS 5/3-8