65 ILCS 5/9-2-15
Whenever any local improvement ordinance is passed by the corporate authorities of any municipality, to be paid for wholly or in part by special assessment, or by special taxation, the making of which will require that private or public property be taken or damaged for public use, the municipality, either in that ordinance or by subsequent order, shall designate some officer to file a petition in the circuit court of the county in which the municipality is situated, or if the municipality is situated in more than one county and the proposed improvement or the property to be taken or damaged, or both, 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. Such petition shall be filed in the name of the municipality, praying that steps may be taken to ascertain the just compensation to be made for private or public property to be taken or damaged for the improvement or purpose specified in the ordinance, and to ascertain what property will be benefited by the improvement, and the amount of those benefits.
65 ILCS 5/9-2-15