Mich. Comp. Laws § 115.21

Sec. 1. Whenever it shall appear upon a census being taken as provided for hereinafter, that the total population of any city, whether such city has been incorporated by virtue of a local act or acts, or under the general laws of the state relating to the incorporation of cities, does not exceed 350 inhabitants, actually residing therein, such city shall not be entitled thereafter to more than 1 representative on the board of supervisors of the county in which such city is located, the provisions of any general law heretofore passed or any local act having application to such city, or the county in which located, to the contrary notwithstanding.