16 U.S. Code § -

With respect to any property acquired by the Secretary of the Interior within a unit of the national park system or miscellaneous area, except property within national parks, or within national monuments of scientific significance, the Secretary may convey a freehold or leasehold interest therein, subject to such terms and conditions as will assure the use of the property in a manner which is, in the judgment of the Secretary, consistent with the purpose for which the area was authorized by the Congress. In any case in which the Secretary exercises his discretion to convey such interest, he shall do so to the highest bidder, in accordance with such regulations as the Secretary may prescribe, but such conveyance shall be at not less than the fair market value of the interest, as determined by the Secretary; except that if any such conveyance is proposed within two years after the property to be conveyed is acquired by the Secretary, he shall allow the last owner or owners of record of such property thirty days following the date on which they are notified by the Secretary in writing that such property is to be conveyed within which to notify the Secretary that such owners wish to acquire such interest. Upon receiving such timely request, the Secretary shall convey such interest to such person or persons, in accordance with such regulations as the Secretary may prescribe, upon payment or agreement to pay an amount equal to the highest bid price.

The Secretary of the Interior is authorized to accept title to any non-Federal property or interest therein within a unit of the National Park System or miscellaneous area under his administration, and in exchange therefor he may convey to the grantor of such property or interest any Federally-owned property or interest therein under his jurisdiction which he determines is suitable for exchange or other disposal and which is located in the same State as the non-Federal property to be acquired: Provided, however, That timber lands subject to harvest under a sustained yield program shall not be so exchanged. Upon request of a State or a political subdivision thereof, or of a party in interest, prior to such exchange the Secretary or his designee shall hold a public hearing in the area where the lands to be exchanged are located. The values of the properties so exchanged, either shall be approximately equal, or if they are not approximately equal, the values shall be equalized by the payment of cash to the grantor from funds appropriated for the acquisition of land for the area, or to the Secretary as the circumstances require.

In order to protect the air, land, water, and natural and cultural values of the National Park System and the property of the United States therein, no solid waste disposal site (including any site for the disposal of domestic or industrial solid wastes) may be operated within the boundary of any unit of the National Park System, other than—

The proceeds received from any conveyance under this section shall be credited to the land and water conservation fund in the Treasury of the United States.