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- Oak Run Township, Madison County, Ohio
- Ohio Township, Clermont County, Ohio
- Ohio Township, Gallia County, Ohio
- Ohio Township, Monroe County, Ohio
- Olive Township, Meigs County, Ohio
- Olive Township, Noble County, Ohio
- Oliver Township, Adams County, Ohio
- Olmsted Township, Cuyahoga County, Ohio
- Orange Township, Ashland County, Ohio
- Orange Township, Carroll County, Ohio
- Orange Township, Cuyahoga County, Ohio (defunct)
- Orange Township, Delaware County, Ohio
- Orange Township, Hancock County, Ohio
- Orange Township, Meigs County, Ohio
- Orange Township, Shelby County, Ohio
- Oregon Township, Lucas County, Ohio (defunct)
- Orwell Township, Ashtabula County, Ohio
- Osnaburg Township, Stark County, Ohio
- Ottawa Township, Allen County, Ohio (defunct)
- Ottawa Township, Putnam County, Ohio
- Oxford Township, Butler County, Ohio
- Oxford Township, Coshocton County, Ohio
- Oxford Township, Delaware County, Ohio
- Oxford Township, Erie County, Ohio
- Oxford Township, Guernsey County, Ohio
- Oxford Township, Tuscarawas County, Ohio
Read more about this topic: List Of Townships In Ohio