A. Buildings for the purposes of any county free fair, which fair exists under any law of this state, may be constructed either upon land owned by the county or upon land which has been leased to the county for a period of not less than fifty (50) years from the time the construction of any such building has started. Any such building may be constructed on leased land owned or leased by the United States or any agency thereof, if not contrary to any conditions imposed by the United States or the agency relating to the land, notwithstanding the fact that the United States or the agency retains the right to take possession of such land in the event of a national emergency.

B. The provisions of this section shall be applicable regardless of the source of the funds from which any such building is constructed.