65 ILCS 5/7-5-3
A copy of the ordinance specified in Section 7-5-2 and an accurate map of the property shall be certified by the mayor or president of the municipality, as the case may be, or by the trustees of the land held as a common, and shall be filed with the recorder in the county where the acquired real estate is situated. When this ordinance and map are so certified and filed, the acquired real estate, whether actually adjoining the former site or territory or not, shall be a part of that municipality or territory, and the inhabitants of the acquired real estate shall be entitled to all the corporate rights, powers, annuities, commons, benefits, and franchises, which the inhabitants of that municipality or territory originally possessed, or to which they were entitled.
65 ILCS 5/7-5-3