Mich. Comp. Laws § 54.231: Michigan coordinate system of 1927 and Michigan coordinate system of 1983 established; division of state into north zone, central zone, and south zone.

Sec. 1.

The systems of plane coordinates which are established by the NOAA/NGS for defining and stating the positions of points on or near the surface of the earth within this state shall be known and designated as the Michigan coordinate system of 1927, or MCS 27, and the Michigan coordinate system of 1983, or MCS 83.

For the purpose of the use of these systems, the state is divided into a north zone, a central zone, and a south zone.

The area included in the following counties constitutes the north zone: Gogebic, Ontonagon, Houghton, Keweenaw, Baraga, Iron, Marquette, Dickinson, Menominee, Alger, Delta, Schoolcraft, Luce, Chippewa, and Mackinac.

The area included in the following counties constitutes the central zone: Emmet, Cheboygan, Presque Isle, Charlevoix, Leelanau, Antrim, Otsego, Montmorency, Alpena, Benzie, Grand Traverse, Kalkaska, Crawford, Oscoda, Alcona, Manistee, Wexford, Missaukee, Roscommon, Ogemaw, Iosco, Mason, Lake, Osceola, Clare, Gladwin, and Arenac.

The area included in the following counties constitutes the south zone: Oceana, Newaygo, Mecosta, Isabella, Midland, Bay, Huron, Muskegon, Montcalm, Gratiot, Saginaw, Tuscola, Sanilac, Ottawa, Kent, Ionia, Clinton, Shiawassee, Genesee, Lapeer, St. Clair, Allegan, Barry, Eaton, Ingham, Livingston, Oakland, Macomb, Van Buren, Kalamazoo, Calhoun, Jackson, Washtenaw, Wayne, Berrien, Cass, St. Joseph, Branch, Hillsdale, Lenawee, and Monroe.