65 ILCS 5/7-1-18
The municipality to which the whole of another municipality is annexed under Section 7-1-16 and 7-1-17 shall assume and pay all debts and liabilities, and shall perform all contracts of the annexed municipality. Upon annexation, the title to all property which belonged to the annexed municipality vests in the annexing municipality, to be held, however, for the same purposes and uses, and subject to the same conditions as before annexation.
The annexing municipality shall assume and pay all debts and liabilities and shall perform all contracts of all school districts and townships wholly within the annexing municipality as it has been enlarged. The annexing municipality is vested with the title to all property belonging to all school districts and townships wholly within the enlarged annexing municipality, to be held, however, for the same purposes and uses and subject to the same conditions as before annexation.
If the bonds of the annexed municipality, or of any school district or township now wholly within the enlarged annexing municipality, have been registered with the State Auditor of Public Accounts, the county clerk of the county wherein the annexing municipality is situated shall certify forthwith the fact of the annexation to the State Auditor. The State Auditor thereafter shall not certify any tax rate to the county clerk, nor shall the county clerk thereafter extend any tax rate, for the payment of the bonds, or interest thereon, merely upon the taxable property in the municipality that has been annexed, or in the school district or township that is wholly within the enlarged annexing municipality. All property in the enlarged annexing municipality, without discrimination between the territory in the annexed and the annexing municipalities, shall be subject to taxation to pay the debts, bonds, and obligations of the municipality. If a portion of a school district or township is within and a portion is without the annexed municipality, the debts and liabilities of that school district or township shall be paid and the property divided in the same manner as is provided in Sections 7-1-31 and 7-1-32.
65 ILCS 5/7-1-18