O.C.G.A. § 36-60-18

No county or municipality within the county shall purchase or accept title to any real property located in an adjoining county, which property will be exchanged for certain property belonging to the federal government as authorized by federal law, without the written consent of the governing authority of such adjoining county wherein the real property is located; provided, however, that the provisions of this Code section shall not apply to the exercise of eminent domain by a county or municipality as authorized under the Constitution or other provisions of law; provided, further, that the provisions of this Code section shall not apply to any agreement entered into by two or more counties, municipal corporations, consolidated governments, or development authorities or any combination thereof prior to July 1, 1994, nor shall the transfer of any land pursuant to any such agreement be affected by this Code section.