O
- (Nishishirakawa-gun) Orikuchihara
- (Yama-gun) Ogikubo
- (Kōriyama Shi) Oyamada
- (Ishikawa-gun) Okudaira
- (Nishishirakawa-gun) Oihara
- (Fukushima Shi) Obara
- (Shirakawa Shi) Omotegō-banzawa
- (Shirakawa Shi) Omotegō-fukaado
- (Higashishirakawa-gun) Okada
- (Iwaki-shi) Ogawamachi-takahagi
- (Iwaki-shi) Ogawamachi-uwadaira
- (Iwaki-shi) Ogawamachi-shioda
- (Futaba-gun) Oragahama
- (Yama-gun) Okugawa-iine
- (Minamiaizu-gun) Otokane
- (Ōnuma-gun) Onogawa
- (Yama-gun) Okugawa-kayane
- (Yama-gun) Okugawa-toyoshima