Mich. Comp. Laws § 247.441

Sec. 41. The county or city at large, or any township at large assessed a per cent for any benefit for the improvement of any highway by the county road commissioners, or by the state highway commissioner, may within 10 days after the final hearing of the review heretofore provided for, appeal therefrom, and for such purpose make an application to the probate court of the proper county for the appointment of a board of review, as hereinafter provided. Townships shall appear by their respective supervisors; and counties shall appear by their clerk and prosecuting attorney; cities shall appear by their chief executive officers or by the city attorney, under the direction of the legislative body of such city. The supervisor shall act upon the direction of his township board. The clerk and prosecuting attorney shall act upon the direction of their board of supervisors, or of a committee of that board to whom may have been referred by the whole board, questions pertaining to the highway improvements. Only 1 application for a board of review shall be entertained by the probate court to review any special assessment.