Ō
- (Tome Shi) Ōizumi
- (Tome Shi) Ōtsunagi
- (Ōsaki Shi) Ōbatake
- (Kami-gun) Ōhira
- (Ōsaki Shi) Ōkuchi
- (Tōda Gun) Ōyanagi
- (Ishinomaki Shi) Ōdomari
- (Ishinomaki Shi) Ōtagiri
- (Ishinomaki Shi) Ōtemachi
- (Ishinomaki Shi) Ōmaki
- (Ishinomaki Shi) Ōmori
- (Ishinomaki Shi) Ōzuchi
- (Ishinomaki Shi) Ōwada
- (Tome Shi) Ōkaizaki
- (Kesennuma Shi) Ōsawa
- (Ishinomaki Shi) Ōharahama
- (Kurihara Shi) Ōhayashi
- (Tōda Gun) Ōhashi
O
- (Ōsaki Shi) Onikōbe
- (Ishinomaki Shi) Oki
- (Ishinomaki Shi) Ouri
- (Ishinomaki Shi) Ojima
- (Ishinomaki Shi) Ogatsuchō-naburi
- (Ishinomaki Shi) Ogatsuchō-mizuhama
- (Ōsaki Shi) Obayashi
- (Sendai) Ogaku
- (Ishinomaki Shi) Okatsuchō-okatsu
- (Ishinomaki Shi) Orinohama
- (Ishinomaki Shi) Ogatsuchō-ōhama
- (Tome Shi) Oinokawara