Mich. Comp. Laws § 600.9928

Sec. 9928. (1) The district court shall not function nor shall district judges be elected in any district of the third class in which 1 or more cities that maintain municipal courts and that contain, individually or in the aggregate, more than 50% of the population of the district elect to retain their municipal courts by resolution adopted by their respective governing bodies not later than June 24, 1968. (2) Municipal courts retained under this section shall perform all duties and powers which by law may be performed by justices of the peace and the circuit court commissioners. (3) The jurisdiction of municipal courts retained under subsection (1) is limited to their respective cities except that if the district contains 1 or more cities that have retained municipal courts under subsection (1) and also contains a city that previously was a village subject to the provisions of section 22a of the home rule village act, 1909 PA 278, MCL 78.22a, but subsequently was incorporated as a city, the newly incorporated city may, by agreement with any 1 of the cities in the district that has retained its municipal court, provide that the municipal court shall exercise the same jurisdiction and powers with respect to the newly incorporated city as it exercises in the city in which it is located. (4) Notwithstanding any other provision of law, a city shall not establish a municipal or police court after July 1, 1968.