In 1831, Arenac County was created by the Territory of Michigan, taken from the Non-County Area 2 that was attached to Oakland County. On 2 March 1836, Arenac County was attached to Saginaw Co “for judicial purposes.” The county was completely eliminated on 20 April 1857 when it was merged into the creation of Bay County. Arenac was re-created 21 April 1883, with boundaries nearly the same as its 1831 Territorial borders. Omer was designated as the county seat. In 1891, Standish was made the county seat.

Since Arenac was part of Bay County from 1857 to 1883, some records during those years may be found in Bay County. Judicial records prior to 1857 may be found in Saginaw County.

All divorce records more than 100 years old are public records.