Mich. Comp. Laws § 600.302

Sec. 302. The state is divided into 4 judicial districts for the election of judges of the court of appeals. Except as otherwise provided in this section, each district is entitled to 7 judges. Beginning on the date as determined under section 303a, each district is entitled to 6 judges. The districts are constituted and numbered as follows: (a) District 1 consists of the counties of Branch, Hillsdale, Kalamazoo, Lenawee, Monroe, St. Joseph, and Wayne. (b) District 2 consists of the counties of Genesee, Macomb, and Oakland. (c) District 3 consists of the counties of Allegan, Barry, Berrien, Calhoun, Cass, Eaton, Ionia, Jackson, Kent, Mason, Montcalm, Muskegon, Newaygo, Oceana, Ottawa, Van Buren, and Washtenaw. (d) District 4 consists of the counties of Alcona, Alger, Alpena, Antrim, Arenac, Baraga, Bay, Benzie, Charlevoix, Cheboygan, Chippewa, Clare, Clinton, Crawford, Delta, Dickinson, Emmet, Gladwin, Gogebic, Grand Traverse, Gratiot, Houghton, Huron, Ingham, Iosco, Iron, Isabella, Kalkaska, Keweenaw, Lake, Lapeer, Leelanau, Livingston, Luce, Mackinac, Manistee, Marquette, Mecosta, Menominee, Midland, Missaukee, Montmorency, Ogemaw, Ontonagon, Osceola, Oscoda, Otsego, Presque Isle, Roscommon, Saginaw, Sanilac, Schoolcraft, Shiawassee, St. Clair, Tuscola, and Wexford.