16 U.S.C. § 460gg-6
The Secretary is authorized to acquire such lands or interests in land (including, but not limited to, scenic easements) as he deems necessary to accomplish the purposes of this subchapter by purchase with donated or appropriated funds with the consent of the owner, donation, or exchange.
The Secretary is further authorized to acquire by purchase with donated or appropriated funds such lands or interests in lands without the consent of the owner only if (1) he deems that all reasonable efforts to acquire such lands or interests therein by negotiation have failed, and (2) the total acreage of all other lands within the recreation area to which he has acquired fee simple title or, lesser interests therein without the consent of the owner is less than 5 per centum of the total acreage which is privately owned within the recreation area on December 31, 1975: Provided, That the Secretary may acquire scenic easements in lands without the consent of the owner and without restriction to such 5 per centum limitation: Provided further, That the Secretary may only acquire scenic easements in lands without the consent of the owner after the date of publication of the regulations required by section 460gg-7 of this title when he determines that such lands are being used, or are in imminent danger of being used, in a manner incompatible with such regulations.
Any land or interest in land owned by the State of Oregon or any of its political subdivisions may be acquired only by donation. Any land or interest in land owned by the State of Idaho or any of its political subdivisions may be acquired only by donation or exchange.
As used in this subchapter the term "scenic easement" means the right to control the use of land in order to protect esthetic values for the purposes of this subchapter, but shall not preclude the continuation of any farming or pastoral use exercised by the owner as of December 31, 1975.
The Secretary shall give prompt and careful consideration to any offer made by a person owning land within the recreation area to sell such land to the United States. The Secretary shall specifically consider any hardship to such person which might result from an undue delay in acquiring his property.
In exercising his authority to acquire property by exchange, the Secretary may accept title to any non-Federal property, or interests therein, located within the recreation area and, notwithstanding any other provision of law, he may convey in exchange therefor any federally owned property within the same State which he classifies as suitable for exchange and which is under his administrative jurisdiction: Provided, That the values of the properties so exchanged shall be approximately equal, or if they are not approximately equal, they shall be equalized by the payment of cash to the grantor or to the United States as the circumstances require. In the exercise of his exchange authority, the Secretary may utilize authorities and procedures available to him in connection with exchanges of national forest lands.
Notwithstanding any other provision of law, the Secretary is authorized to acquire mineral interests in lands within the recreation area, with or without the consent of the owner. Upon acquisition of any such interest, the lands and/or minerals covered by such interest are by this subchapter withdrawn from entry or appropriation under the United States mining laws and from disposition under all laws pertaining to mineral leasing and all amendments thereto.
Notwithstanding any other provision of law, any Federal property located within the recreation area may, with the concurrence of the agency having custody thereof, be transferred without consideration to the administrative jurisdiction of the Secretary for use by him in carrying out the purposes of this subchapter. Lands acquired by the Secretary or transferred to his administrative jurisdiction within the recreation area shall become parts of the national forest within or adjacent to which they are located.
16 U.S.C. § 460gg-6