70 ILCS 705/14.01
Any two or more adjoining fire protection districts may merge and form a single consolidated district which shall thereafter be subject to the provisions of this Act. For the purpose of this Section and Sections 14.02 through 14.13, districts shall be considered as adjoining when any portion of their boundaries are contiguous or overlap, or when a portion of the boundaries of each of the districts seeking to merge to form a consolidated district is contiguous with the same municipality and are served by the same fire department or fire protection department. When the proposed consolidated district will include more than two districts, it shall not be necessary for each district to adjoin each of the other districts, but it shall be sufficient if each district adjoins one of the other districts or if each district adjoins the same municipality.
70 ILCS 705/14.01