The boundaries of Rocky Mountain National Park, the Roosevelt National Forest, and the Arapaho National Forest are revised as generally depicted on the map entitled “Boundary Adjustments, Rocky Mountain National Park”, numbered 121–80,047, dated October 1, 1979, which shall be on file and available for public inspection in the Office of the Director, National Park Service, Department of the Interior, and the Office of the Chief, Forest Service, Department of Agriculture: Provided, That the area shown on such map as E–5 and known as the Twin Sisters area shall remain a part of the Rocky Mountain National Park. All lands added or transferred by this Act to Rocky Mountain National Park, Roosevelt National Forest, and Arapaho National Forest shall be subject to the laws and regulations applicable to the appropriate National Park or National Forest. Lands within the Indian Peaks Wilderness Area as designated by Public Law 95–450 (92 Stat. 1099) [16 U.S.C. 460jj et seq.], that are transferred by this Act to Rocky Mountain National Park shall remain in the National Wilderness Preservation System. Lands within the Rocky Mountain National Park that are adjacent to the Indian Peaks Wilderness and that are transferred by this Act to the Roosevelt National Forest shall be incorporated in and become part of the Indian Peaks Wilderness.

The Secretary of the Interior, with respect to lands added or transferred by this Act to Rocky Mountain National Park, and the Secretary of Agriculture, with respect to lands added or transferred by this Act to Roosevelt and Arap­aho National Forests, may acquire lands and interests in such lands, by donation, purchase with donated or appropriated funds, or by exchange. The Secretary of Agriculture, under sections 485 and 486 of this title, may accept on behalf of the United States title to any land in section 30, township 7 north, range 73 west, of the sixth principal meridian which lies within the boundary of Rocky Mountain National Park as revised by this Act, in exchange for which the Secretary of the Interior, notwithstanding section 1279(a) of this title, is authorized to issue patent to lands lying within the Cache La Poudre Wild and Scenic River study corridor. Upon completion of the exchange, the Secretary of Agriculture shall transfer to the administrative jurisdiction by the Secretary of the Interior the portion of such land lying within the boundary of the Rocky Mountain National Park as revised by this Act.

The Federal lands within the administrative jurisdiction of the Bureau of Land Management and within the areas referred to as E–2 and GL–3 on the map referred to in subsection (a) shall be transferred to Rocky Mountain National Park without transfer of funds.

If the city of Longmont, Colorado, notifies the Secretary of the Interior that lands within the area referred to as E–8 on the map referred to in subsection (a) of this section that are owned by such city are necessary for the development of a reservoir, the Secretary shall by publication of a revised boundary description in the Federal Register revise the boundary of Rocky Mountain Park within such area to exclude the lands which are necessary for the development of the reservoir: Provided, That the authority of such Secretary to revise the boundary for this purpose shall expire on November 1, 1981; and the only lands which may be excluded are the approximately one hundred twenty-nine acres owned by such city.

If after the completion of two complete fiscal years following December 22, 1980, the Secretary of the Interior has not purchased interests in the lands of approximately one thousand two hundred acres known as the Old McGregor Ranch located within the area referred to as E–2 on the map referred to in subsection (a), and the owner of such lands petitions the Secretary to exclude such lands from Rocky Mountain National Park, the Secretary shall by publication of a revised boundary description in the Federal Register return the boundary of Rocky Mountain National Park in such area E–2 to the boundary as it existed before December 22, 1980.

The Secretary of the Interior shall convey, to the city of Grand Lake, Colorado, without compensation or consideration, the lands, not to exceed two acres, within the area referred to as GL–5 on the map referred to in subsection (a).

The Secretary of the Interior may provide for the use of snowmobiles along the East Shore Trail of Shadow Mountain Lake if after study the Secretary determines such use will not result in any significant adverse impact upon wildlife.