35 ILCS 200/3-45
Election of county assessor; counties of less than 3,000,000. In counties having an elected board of review under Section 6-35, a county assessor shall be elected. To be eligible to file nomination papers or participate as a candidate in any primary or general election for, or be elected to, the office of county assessor, or to enter upon the duties of the office, a person must possess one of the following qualifications as certified by the individual to the county clerk:
The county clerk must determine if candidates for assessor have qualified under this Code prior to certification of their nominating petitions. The election of the county assessor shall be at the same time and in the same manner as other county officials are elected under the general election law. The county assessor shall hold office for a 4 year term and until a successor is elected and qualified. Vacancies shall be filled in the same manner as are vacancies in other county elective offices.
35 ILCS 200/3-45