Michigan Marriage Index: Sarah Partlow, Dece 23, 1858 to Stephen Thomas, Ionia County Michigan, film # 0960508-0960510
Then I looked up the address for the county clerks office they also have marriage records from 1837. If you sent for their marriage certificate it should show who Sarah's parents were and where she was actually born.
Ionia County 100 E. Main St. Ionia, Michigan 48844
phone 616-527-5322. You might want to call them and see what the cost of a copy forthe marriage cert is.
my email is firstname.lastname@example.org for further contact