86 Ill. Adm. Code 130.1205
Due Date that Falls on Saturday, Sunday or a Holiday
Section 130
Section 130.1205 Due Date
that Falls on Saturday, Sunday or a Holiday
If the due date for any return
or other report or payment falls on Saturday, Sunday or a Holiday, such due
date shall be considered to be the next business date either for the purpose of
submitting such return or other report or payment by mail or for the purpose of
submitting such return or other report or payment in person.