50 ILCS 605/4
Any municipality shall have the power upon resolution passed by a two-thirds vote of the members of its legislative body then holding office, to transfer all of the right, title and interest held by it immediately prior to such transfer, in and to any real estate, whether located within or without such municipality, to the State of Illinois, for any authorized purpose of state government, upon such terms and conditions as may be agreed upon by the transferor municipality and the State of Illinois, and the State of Illinois is authorized to accept the title or interest in such real estate so conveyed; except that a majority vote of the members of such legislative body then holding office is sufficient for the dedication by any municipality of any area as a nature preserve as provided in the "Illinois Natural Areas Preservation Act" as now or hereafter amended. If such real estate is held by the transferor municipality subject to or limited by any restriction, the State of Illinois, by the Secretary of Transportation or by the Director of any state department, or the Chairman or President of any commission, board or agency of the State vested by law with the power, duty or function of the State Government for which said property is to be used by the State after its acquisition, may remove such restriction through purchase, agreement or condemnation. Any such condemnation proceedings shall be brought and maintained by the State of Illinois and shall conform, as nearly as may be, with the procedure provided for the exercise of the power of eminent domain under the Eminent Domain Act .
50 ILCS 605/4