65 ILCS 5/7-1-26
Any territory containing 60 acres or less lying along one or both sides of the boundary line between 2 adjoining municipalities, and contiguous to a third municipality may be excluded from one or both of the adjoining municipalities and annexed to the third contiguous municipality, as follows:
The corporate authorities of the excluding municipalities or municipality shall, by majority vote of the corporate authorities then holding office, adopt an ordinance providing for such exclusion, and the corporate authorities of the annexing municipality shall adopt an ordinance providing for the annexation of this territory. Upon the adoption of these ordinances, the territory is thereby excluded from the excluding municipalities and added to the annexing municipality. The chief executive officer of each municipality thereupon shall file for recordation an accurate map of the excluded or added territory, as the case may be, together with a certified copy of the ordinance for exclusion or annexation with the recorder of the county in which the excluded or added territory, as the case may be, is situated. The ordinance shall be published in a newspaper of general circulation in the excluding and annexing municipalities and shall contain a notice of (1) the specific number of voters required to sign a petition requesting the question of disconnection and annexation to be submitted to the electors; (2) the time in which such petition must be filed; and (3) the date of the prospective referendum. The clerks of the municipalities in which the territory is sought to be disconnected or annexed shall provide a petition form to any individual requesting one.
Whenever any disconnection and annexation shall be effected as provided in this Section any taxpayer in such area disconnected and annexed may, within 10 days after adoption of the annexing ordinance, file with the clerk of the circuit court in the county wherein the disconnected and annexed area is located a petition signed by not less than 10% or 100, whichever is lesser, of the electors of the area disconnected and annexed, requesting the submission to a referendum of the following proposition: "Shall the territory (here describe it) be disconnected from the municipality of .... and annexed to the municipality of ....?"
The circuit court, if it finds the petition to be in conformity with law, shall order that the proposition be submitted at an election to be conducted in accordance with the general election law. The clerk of the circuit court shall certify the proposition to the proper election authority for submission. If a majority of the voters voting on the proposition vote in favor thereof, such disconnection and annexation shall be valid and binding. If a majority of the vote is against such proposition the disconnection ordinance adopted by the disconnecting municipality and the annexation ordinance adopted by the annexing municipality shall be void.
65 ILCS 5/7-1-26