55 ILCS 5/3-11011
Of the banks, savings and loan associations, savings banks, or credit unions which may have been so designated as depositories, one shall be designated from time to time by the county treasurer as the active bank, depository, savings and loan association, savings bank, or credit union for a period of not more than one month at a time. The county board shall have power, if it sees fit, to require that no bank, savings and loan association, savings bank, or credit union whose aggregate capital stock and surplus is less than a certain specified amount shall be named as the active bank, savings and loan association, savings bank, or credit union. During such period the county treasurer shall draw all of his checks to pay warrants and other demands drawn upon him upon such active bank, savings and loan association, savings bank, or credit union: Provided, however, that the county treasurer shall have power to withdraw county moneys from any depository for the purposes stated in Section 3-11010: And, provided, further, that during such period drafts and checks against deposit of funds designated by Section 3-11003 hereof as "Class A" funds and "Class B" funds may be drawn upon other than the active bank, savings and loan association, savings bank, or credit union.
55 ILCS 5/3-11011