70 ILCS 1205/3-6b
The owner or owners of record of any area of land consisting of one or more tracts located in a county or counties having a population of less than 1,000,000 lying within the corporate limits of any park district which (1) is not contiguous in whole or in part to any other park district; (2) contains 20 or more acres; (3) is not subdivided into municipal lots and blocks; (4) is located on the border of the park district, (5) which, if disconnected will not result in the isolation of any part of the park district from the remainder of the park district, and (6) which, if disconnected will not result in reducing the assessed valuation, as equalized or assessed by the Department of Revenue, of all of the taxable property within the park district to be ascertained by the last assessment for state and county taxes prior to the filing of the petition, to less than $20,000,000, may have the area disconnected as follows:
The owner or owners of record of any such area shall file a petition in the circuit court of the county in which the land is situated, alleging facts in support of the disconnection. If such area of land is located in 2 or more counties, such petition shall be filed in the circuit court of the county in which the largest portion of such area of land is located. The park district from which disconnection is sought shall be made a defendant and it or any taxpayer residing in the park district may appear and defend against the petition. If the court finds that the allegations of the petition are true, and that the area of land is entitled to disconnection, it shall order the designated land disconnected from the designated park district. Such petition shall be filed within one year after the park district is organized.
This Section shall apply only to park districts which are organized after the effective date of this amendatory Act.
70 ILCS 1205/3-6b