35 ILCS 200/3-10
The county board, by a vote of 2/3 of its members, may dismiss a supervisor of assessments before the expiration of his or her term for misfeasance, malfeasance or nonfeasance in the performance of the duties of the office. Whenever the county board dismisses a supervisor of assessments, it shall specify its reasons in writing. The dismissed supervisor may, within 21 days after receipt of the statement of reasons for dismissal, request a hearing before the county board. The county board shall conduct a hearing within 30 days of a timely request, and may reverse the dismissal by a vote of a majority of the members present.
Vacancies shall be filed by appointment for a full term. In the event of a vacancy, the county board may appoint an acting supervisor of assessments, but an acting supervisor may serve for no more than 60 days until a qualified person is appointed to fill the remainder of the term.
35 ILCS 200/3-10