Shiawassee County, Michigan: History
In 1822, the Michigan Territorial legislature defined a new county, Shiawassee (named for the Shiawassee River), taken from portions of existing Oakland and St. Clair counties. However, for purposes of representation, revenue, and judicial matters, the area was temporarily assigned to adjoining county governments. In early 1837, the Michigan Territory was admitted into the Union as the State of Michigan, and that same year the new Michigan State government authorized the organization of a county government in Shiawassee.