70 ILCS 1205/3-3a
Where territory to be annexed includes any part of a municipality not currently a part of any park district, that territory must include the municipality in its entirety. The board of any park district may initiate the proceedings by enacting an ordinance expressing its desire to annex the territory, or any 100 or more legal voters residing within the municipality proposed to be annexed may petition to initiate annexation proceedings. The ordinance or petition shall be filed with the clerk of the circuit court where the park district or a greater or greatest portion lies. The ordinance or petition shall set forth the name of the park district to which annexation is proposed and define the limits of the territory proposed to be annexed. Upon the filing of the petition, the court shall determine its validity and, if it is in conformity with law, shall order the proposition submitted to referendum as provided in Section 3-3. The changes made to this Section by this amendatory Act of 1991 clarify the language and make no substantive changes.
70 ILCS 1205/3-3a