Mich. Comp. Laws § 600.4025

Sec. 4025. The county which would be a proper county of venue as designated in RJA chapter 16 of an action against the defendant who is garnisheed is a proper county of venue for garnishment if (1) the county is designated in RJA chapter 16 as a proper county of venue of the action against the principal defendant; or (2) there is no common proper county of venue designated in RJA chapter 16 of an action against the principal and garnishee defendant; or (3) personal jurisdiction cannot be obtained over the principal defendant.