70-22-201. Coordinate systems adopted -- designation -- division of state into zones. (1) The North American datum systems of plane coordinates that have been established by the national ocean survey/national geodetic survey (formerly the United States coast and geodetic survey) or a successor for defining and stating the positions or locations of points on the surface of the earth within the state of Montana are hereafter to be known and designated as the "Montana coordinate system NAD 27" and the "Montana coordinate system NAD 83".

(2) For the purpose of the use of the Montana coordinate system NAD 27, the state is divided into a north zone and a central zone and a south zone as provided in subsections (3) through (5).

(3) The area now included in the following counties shall constitute the north zone: Blaine, Chouteau, Daniels, Flathead, Glacier, Hill, Liberty, Lincoln, Phillips, Pondera, Roosevelt, Sheridan, Teton, Toole, and Valley.

(4) The area now included in the following counties shall constitute the central zone: Cascade, Dawson, Fergus, Garfield, Judith Basin, Lake, Lewis and Clark, McCone, Meagher, Mineral, Missoula, Petroleum, Powell, Prairie, Richland, Sanders, and Wibaux.

(5) The area now included in the following counties shall constitute the south zone: Beaverhead, Big Horn, Broadwater, Carbon, Carter, Custer, Deer Lodge, Fallon, Gallatin, Golden Valley, Granite, Jefferson, Madison, Musselshell, Park, Powder River, Ravalli, Rosebud, Silver Bow, Stillwater, Sweet Grass, Treasure, Wheatland, and Yellowstone.

(6) For the purpose of the use of the Montana coordinate system NAD 83, the state is a single zone.