70 ILCS 1230/2
In all cases in which said board of park commissioners shall have acquired or contracted to acquire the riparian rights of the owners of any lands along the shore adjoining such public waters or rivers, or have acquired or contracted to acquire lands owned or claimed by such owners, and have agreed upon the dividing line aforesaid, such board of park commissioners shall file petitions or complaints in the circuit court of the county in which such lands are situated, praying that the boundary line between the lands acquired or to be acquired by the defendants in such suit and the lands acquired or to be acquired by such board of park commissioners under this Act and under such contracts, may be established and confirmed by the judgment of such court, as agreed upon by such parties, to which complaints or petitions all persons interested in such riparian rights and lands as owners or otherwise as appearing of record, if known, or if not known, stating that fact, shall be made defendants. Persons interested whose names are unknown, may be made parties defendants by the description of the unknown owners; but in all such cases, an affidavit shall be filed by or on behalf of the petitioner or plaintiff, setting forth that the names of such persons are unknown; such board of park commissioners shall also give public notice of the filing of each such complaint or petition by publication thereof once a week for 3 consecutive weeks in a newspaper of general circulation regularly published in the city in which or nearest to which such riparian rights or lands are situated, which notice shall contain the title of the suit and the designation of a return day at which the defendants are to appear, the last of which notices shall be published not less than 10 days or more than 20 days before the day so designated for appearance. The defendants who do not enter their appearance shall be served with process in the suits so instituted in the same manner as in other civil suits, and the proceedings in such cause shall be conducted in the same manner as in other civil suits. Any legal voter or taxpayer within the district or territory in which the property shall be taxable for the maintenance of the park system under the control of such board of park commissioners, shall be permitted to enter his appearance and become a party defendant in the proceedings and may answer or may file any appropriate motion as in other civil cases. If, upon a hearing, the court shall find that the rights and interests of the public have been duly conserved in and by such an agreement, then the court shall confirm such agreement and establish such boundary line; otherwise, the court shall, in its discretion, dismiss such complaint or petition. If the dividing line agreed upon shall be so established and confirmed by the judgment of the court, it shall thereafter be the permanent dividing and boundary line of such lands, and shall not be affected or changed thereafter, either by accretions or erosions; and the owners of such short lands are hereby granted by the State of Illinois, the title to the adjacent, adjoining, submerged, penetrating and other lands, whether of natural or artificial formation, lying upon the inner or land side of said boundary line when so established, and they shall have the right to fill in, improve, protect, use for all lawful purposes, sell and convey the submerged or other lands up to the line so established, free from any adverse claim in any way arising out of any question as to where the shore line was at any time in the past, or as to the title to any existing accretions, and the board of park commissioners is hereby granted by the State of Illinois, the title for park purposes to the adjacent, adjoining, submerged, penetrating, artificially made and other lands lying upon the outer or water side of the boundary line and opposite and adjoining to the lands granted and confirmed by such judgment to such riparian, shore or other owners. It shall be the duty of the Attorney General to appear in such proceedings and assert the claim of the State of Illinois, if any, as to any lands involved in such proceeding, which have been improperly taken, made or occupied, and the court shall proceed to hear and determine such claim in the proceeding. If it shall be found that any land has been wrongfully taken, made or occupied to which the State of Illinois can assert title, it shall be the duty of the court to enter a judgment requiring proper compensation to be made by the person or persons or corporation taking, making or occupying such lands, or in lieu thereof to vacate the same, and such compensation and the claim of the Attorney General shall be determined before any such agreement between any park board and the alleged owners of such lands shall in any way become effective. The Attorney General shall have the right, upon behalf of the State with the approval of the court, to compromise any claim which the State of Illinois may assert upon such terms as shall be just and equitable to the State of Illinois. The court shall require notice of the pendency of such proceeding to be given to the Attorney General, and before any judgment shall be entered in such proceeding, proof shall be made that such notice has been given.
70 ILCS 1230/2