55 ILCS 5/5-38003
The public county library service except in counties where such a service is maintained by contract with an existing library or libraries, shall be under the direct supervision and control of a county library board. This board shall consist of five members, who shall be appointed by the presiding officer of the county board with the advice and consent of the county board. Of the first members to be appointed, one member shall be appointed for a term of one year, one for a term of two years, one for a term of three years, one for a term of four years, and another for a term of five years. Thereafter, upon the expiration of each of these terms, the members of the county library board shall be appointed for terms of five years each. A vacancy upon the county library board shall be filled for the unexpired portion of the term in like manner. In counties where the public county library service is maintained by contract with an existing library or libraries, the making and performance of any such contract shall be under the supervision of the county board.
55 ILCS 5/5-38003