75 ILCS 5/4-3
The election of the 7 trustees for the first board of library trustees shall be held at the time of the library establishment election. If a majority of the votes cast in any incorporated town or village (except a village under the commission form of government) on the proposition pursuant to Section 2-2 are in favor of the establishment of a public library, the 7 persons who receive, for the respective terms designated on the ballot, the highest number of votes for library trustees cast at such election shall constitute the board of library trustees. Two of these terms shall be until the next election held in an odd-numbered year in the incorporated town, village or township, 2 shall be until the second such election after the election establishing the library, and 3 shall be until the third such election after the election establishing the library. The trustees so elected shall serve until their successors are duly elected and qualified in accordance with the provisions of this Article.
75 ILCS 5/4-3