65 ILCS 5/7-1-33
Upon annexation, the title and possession of all municipal and school property located in the annexed part vests in the annexing municipality. There shall be an adjustment of the municipal and school properties owned by the municipality, school district, or township from which a part is disconnected in order that all of this property may be divided between that municipality, school district, or township and the enlarged annexing municipality, on the same basis and by the same authorities or court as is provided in Sections 7-1-31 and 7-1-32 for a division of indebtedness and liabilities. If the public property that becomes vested in the enlarged annexing municipality because of its location in the part that was disconnected and annexed exceeds in value the proportionate part to which the annexing municipality is thus entitled, then the enlarged annexing municipality shall pay to the municipality, school district, or township, as the case may be, a sum equal to the difference between what it received and what it should have received on the basis specified in Sections 7-1-31 and 7-1-32 for the division of indebtedness and liabilities. Likewise, if the public property located in that part of the municipality, school district, or township, that remains after the disconnection occurs, exceeds in value the proportionate part to which the municipality, school district, or township is entitled, then the municipality, school district, or township, as the case may be, shall pay to the enlarged annexing municipality a sum equal to the difference between what it received and what it should have received on the basis specified in Sections 7-1-31 and 7-1-32 for the division of indebtedness and liabilities.
65 ILCS 5/7-1-33