- Ōyachi
- Osarushinai
- Okukuchoro
- Okuosotsubetsu
- Okushumbetsu
- Omonai
- Osotsubetsu-gen’ya
- Otsunishi
- Ōiwa
- Ōmagari
- Ōmachi
- Oroshimachi
- Ōta
- Obirashike
- Oshamappu
- Ōinosawa
- Ōkawachō
- Okotsu
- Oku-muri
- Ōmachi
- Onbetsu-motomachi
- Onbetsuchō-akebono
- Onbetsuchō-asahi
- Onbetsuchō-chanbetsu
- Onbetsuchō-shakubetsu
- Onbetsuchō-chokubetsu-gen’yahigashi-sansen
- Onbetsuchō-chokubetsu-gen’yakisen
- Onbetsuchō-fūren
- Onbetsuchō-kaikō
- Onbetsuchō-kawahigashi