How to pay property tax in Illinois

2 sourced points for Illinois, each linked to the official page it comes from.

Your county treasurer prepares and mails the property tax bills and collects the payments. tax.illinois.govOct 21
You still owe the tax even if your bill never arrives. mcleancountyil.govOct 21

The dates

Date and source	Deadline	Applies to
Varies, see rule set by noticetax.illinois.govOct 21	Bills due Two installments, set by the county Most counties bill in two installments, usually June 1 and September 1. If bills go out after May 1, the first installment is due 30 days after the bill date. Your county treasurer sets the real dates.	All 101 Illinois counties except Cook