330 ILCS 56/15

A private employer may adopt and apply a voluntary veterans' preference employment policy if: (1) the veterans' preference employment policy is in writing; (2) the veterans' preference employment policy is publicly posted by the private employer at the place of employment or on any website maintained by the private employer; (3) the private employer's job application informs all applicants of the veterans' preference employment policy and where the policy may be obtained; and (4) the private employer applies the veterans' preference employment policy uniformly for all employment decisions regarding the hiring or promotion of veterans or the retention of veterans during a reduction in force.