35 ILCS 200/20-55
Township collectors shall return the tax books and make final settlement for the amount of taxes placed in their hands for collection, within 60 days after receiving the tax books, except the county collector may first notify, in writing, the several township collectors upon what day, within 20 days after the expiration of 60 days from the day the tax books are received by the township collector, that they shall appear at his or her office to make final settlement. Township collectors in townships organized under the provisions of Article 15 of the Township Code shall make a partial settlement with the county collector of all taxes collected at the expiration of 60 days from the day the tax books are received by the township collectors, but shall retain the tax books until on or before the first day of September at which time they shall make final settlement for the amount of taxes placed in their hands for collection together with the amount of interest and penalties which may have accrued thereon, which interest and penalties the township collector shall collect, and return the tax books to the county collector. In the 10 years following the completion of a general reassessment of property in any county with 3,000,000 or more inhabitants, made under an order of the Department, the return and settlement shall be made on or before the twenty-first day after the day specified by the county clerk for the delivery of the books for the collection of taxes to the collectors, but the county collector may first notify in writing the several township collectors upon what day within 20 days after the 21 day period they shall appear at his or her office to make final settlement.
35 ILCS 200/20-55