Ill. Admin. Code tit. 14, § 178.30
b) Documents submitted for filing in Springfield, the Department's headquarters, shall be filed at the following address:
Secretary of State's Office
Department of Business Services
Limited Liability Company Division
Room 351, Howlett Building
Springfield, Illinois 62756
(Source: Amended at 27 Ill. Reg. 8884, effective May 19, 2003)