When Arenac County was separated out of Bay County and organized in 1883, Omer was designated as the county seat. The Omer courthouse burned in 1889 and was promptly rebuilt but only two years later popular vote selected Standish to be the county seat. The rebuilt Omer courthouse stands today as Ye Olde Courthouse and Masonic Hall, an Arenac County Historical Society project. It is a Michigan State Historic Site and is listed on the National Register of Historic Places.

Entries are listed by locale, then by date. If an index spans a range of years, it’s placed according to the earliest year.