Illinois Statutes Chapter 35. Revenue § 1010/1-90. Service of process and mailings

(a) Mailings by first class or certified or registered mail, postage prepaid, to the address of the taxpayer given on the taxpayer's petition, or to the address of the taxpayer's representative of record, if any, or to the usual place of business of the Department, shall constitute personal service on the other party. The Tax Tribunal may by rule prescribe that notice by other means shall constitute personal service and may in a particular case order that notice be given to additional persons or by other means.

(b) Mailing by registered or certified mail and delivery by a private delivery service approved by the Internal Revenue Service in accordance with Section 7502(f) of the Internal Revenue Code of 1986, as amended, shall be deemed to have occurred, respectively, on the date of mailing and the date of submission to the private delivery service.