55 ILCS 5/3-1006

In counties of 275,000 population or less, as determined by the last federal decennial census, the county auditor, in addition to the duties prescribed in Section 3-1005, shall: (a) Be the general accountant of the county and keep its general accounts. (b) Devise and install a system of financial records in the offices and divisions of the county, to be followed in such offices and divisions. Such a system shall be suitable to the needs of the office and in accordance with generally accepted principles of accounting for governmental bodies.