Compiled Laws, Chapter 168. Michigan Election Law § 168.623a

Sec. 623a. (1) On or before April 1 in even numbered years, the chairperson of the county committee or district committee of a congressional district or a part of a congressional district considered a county under section 592  1 of each political party shall forward by mail or otherwise deliver to the board of election commissioners in that county a certificate showing the number of delegates to the county convention to which each precinct of the county is entitled. The chairperson of the state central committee of a political party shall notify the chairperson of the county committee or district committee of a congressional district or a part of a congressional district considered a county under section 592 of that political party no later than March 1 in even numbered years that the certificate required by this subsection is to be delivered to the board of election commissioners on or before April 1 of that year.

(2) If the chairperson fails to forward the certificate required by subsection (1) by the day specified, the board of election commissioners shall immediately determine the number of delegates to the county convention that each precinct should elect for the implementation of this act.

(3) The allotment of delegates to all precincts in the state shall be made to insure, as near as is practicable, equal apportionment based upon the total vote cast for the candidate of each political party for either president of the United States or secretary of state at the last general November election when elections for those offices were held, whichever is later. However, each precinct shall have at least 1 delegate.

(4) The apportionment shall be based on the precincts as they exist 180 days before the August primary election in even numbered years.

(5) As many delegates in each precinct as a political party is entitled to according to the certificate authorized by the chairperson of the county committee or the board of election commissioners shall be elected at the August primary in even numbered years by direct vote of the registered electors of each political party in the county.