Idaho Code § 70-1508
Any two (2) or more port districts shall have the power, by mutual agreement, to exercise jointly all powers granted to each individual district, and in the exercise of such powers shall have the right and power to acquire jointly all lands, property, property rights, leases, or easements necessary for their purposes, either entirely within, or partly within and partly without, or entirely without such districts; provided that any two (2) or more districts so acting jointly, by mutual agreement, shall not acquire any real property or real property rights in any other port district without the consent of such district. A port district may enter into any contract with the United States, or any state, county or municipal corporation, or any agency or instrumentality thereof, for carrying out any powers which each of the contracting parties may by law exercise separately.
Idaho Code § 70-1508