16 U.S.C. § 1135
The Secretary of Agriculture may accept gifts or bequests of land within wilderness areas designated by this chapter for preservation as wilderness. The Secretary of Agriculture may also accept gifts or bequests of land adjacent to wilderness areas designated by this chapter for preservation as wilderness if he has given sixty days advance notice thereof to the President of the Senate and the Speaker of the House of Representatives. Land accepted by the Secretary of Agriculture under this section shall be come part of the wilderness area involved. Regulations with regard to any such land may be in accordance with such agreements, consistent with the policy of this chapter, as are made at the time of such gift, or such conditions, consistent with such policy, as may be included in, and accepted with, such bequest.
The Secretary of Agriculture or the Secretary of the Interior is authorized to accept private contributions and gifts to be used to further the purposes of this chapter.
16 U.S.C. § 1135