60 ILCS 1/15-30
After August 11, 1986, whenever territory is disconnected from a township and connected to a coterminous township before the effective date of this amendatory Act of the 94th General Assembly, the coterminous city shall provide, on or before December 31 of each year for a period of 10 years, to the township from which the territory was disconnected an amount equal to the real estate tax that was collected on the property in the tax year immediately preceding the disconnection. Whenever territory is disconnected from a township and connected to a coterminous township on or after the effective date of this amendatory Act of the 94th General Assembly, the coterminous city shall provide to the township from which the territory was disconnected, for a period of 10 years: (i) no later than 60 days after the first due date for real estate taxes in that county for that tax year, an amount equal to at least 50% of the real estate tax that was collected on the property in the tax year immediately preceding the disconnection and (ii) on or before December 31 of each year an amount equal to 50% of the real estate tax that was collected on the property in the tax year immediately preceding the disconnection.
60 ILCS 1/15-30