35 ILCS 200/20-140
Subject to the provisions of the Public Funds Statement Publication Act and Sections 3.1-35-60 through 3.1-35-80 of the Illinois Municipal Code, the county collector in counties with 3,000,000 or more inhabitants, shall on the first day of June and the first day of every month thereafter pay over to the other proper authorities or persons the amounts in his or her possession and payable to them as taxes and not previously paid over. In counties with less than 3,000,000 inhabitants, the county collector shall (i) pay over to the other proper authorities or persons, as provided in Section 20-130, the amounts in the collector's hands and payable to them as taxes and (ii) together with the final payment, pay over to the other proper authorities or persons the amounts in the collector's hands and payable to them as interest and not previously paid over. The county treasurer shall determine the manner in which all payments required by a county collector under this Section are to be made. The manner of payment may include, but is not limited to, check or electronic funds transfer. Taxes collected in counties with less than 3,000,000 inhabitants and not distributed shall be invested in accordance with Section 1 of the Public Funds Deposit Act.
35 ILCS 200/20-140