70 ILCS 2405/22a.11
Upon the passage of any ordinance for a local improvement the district, by and through an attorney employed for that purpose, shall file a petition in the circuit court in the county where the affected territory lies, or if the district is situated in more than one county and the proposed improvement lies in more than one county, then in the circuit court in the county in which the major part of the territory to be affected thereby is situated, in the name of the district, requesting that steps be taken to levy a special assessment for the improvement in accordance with the provision of that ordinance. There shall be attached to or filed with this petition a copy of the ordinance, certified by the clerk under the corporate seal, and also a copy of the recommendation of the committee of local improvements and of the estimate of cost as approved by the board. The failure to file any of these copies shall not affect the jurisdiction of the court to proceed in the cause and to act upon the petition, but if it appears in any such cause that the copies have not been attached to or filed with the petition before the filing of the assessment roll therein, then, upon motion of any objector for that purpose on or before appearance day in the cause, such copies shall be so filed. The several circuit courts of this State have jurisdiction of any proceeding under this Act.
70 ILCS 2405/22a.11