40 ILCS 5/7-220

The provisions of the Administrative Review Law, and all amendments and modifications thereof and the rules adopted pursuant thereto shall apply to and govern all proceedings for the judicial review of final administrative decisions of the retirement board provided for under this Article. The term "administrative decision" is as defined in Section 3-101 of the Code of Civil Procedure. The venue for actions brought under the Administrative Review Law shall be any county in which the Board maintains an office or the county in which the member's employing participating municipality or participating instrumentality has its main office.