Regions of Japan
- Ōmu
- Ōmori-yama
- Ōmori
- Ōmisawa Machi
- Ōminato-wan
- Ōminato-machi
- Ōminato-kō
- Ōminatochō
- Onbetsu Gawa
- Onbetsu-motomachi
- Oma Cape
- Ō-mata-gawa
- Ōma-se
- Ōma Machi
- Ōma Kō
- Utanobori-ōmagari
- Ohmagari
- Ōmagari
- Ōmachi
- Ōmachō
- Ōma
- Ōkuzo
- Hinaimachi-ōkuzo
- Okuyuki
- Okushumbetsu
- Okushibetsu-gawa
- Chiyoda
- Oku-setose
- Okuse
- Okusawachō
- Okurige
- Ōkura Dake
- Oku-muri
- Okumo-okoppe
- Okumaru Yama
- Oku-kombu
- Ōkuki
- Oku-ikutahara
- Okori-se
- Okoppe Gawa
- Okoppe Chō
- Okoppe
- Okonshibe
- Okohachi-yama
- Okobachi-gawa
- Okishinai
- Oki-se
- Okino-shō
- Okino-se
- Okino-se
- Okino-se
- Okinai-yama
- Okimura-gawa
- Okimura
- Okidate Gawa
- Okidate
- Oketo-dake
- Oketo
- Ōkenashi Yama
- Ōkawamachi
- Ōkawa
- Ōkawa
- Okajima
- Okadamachō
- Ōjimachi
- Ōji
- Oiwake Tōge
- Oiwakechō
- Oiwake
- Oiwake-honmachi
- Ōiso
- Oirase-gawa
- Oipe-gawa
- Ōinosawa
- Oikamanai Numa
- Oikama
- Oide
- Ohō-dake
- Ōhata-machi
- Ōhata-gawa
- Ōhata
- Ōbana Misaki
- Ohanabe Yama
- Ōhama-gawa
- Shiomi
- Oguruma Dake
- Ōkuro Mori
- Okuri Yama
- Ogura Yama
- Kogura Dake
- Okuno
- Ogifushi-hana
- Ogifushichō
- Ōgita
- Hinaimachi-ōgita
- Ogawashiro-yama
- Ogawara Ko
- Ogawara
- Ofuyu-yama
- Ofuyu-misaki
- Ofuyu
- Ōfunechō
- Ofukeshi
- Ōfukanai Mura
- Ōekōzan
- Ōe
- Ōe
- Ōdose Saki
- Ōdōri
- Ōdomari
- Ōdate-shi
- Ōdate-machi
- Ōdate Bonchi
- Ōdate
- Ōdate
- Ō Take
- Ōkomaga Dake
- Odaitō
- Ōdaira
- Ōdai
- Oda
- Ochūshinai
- Ochikiri
- Ochiishi Wan
- Ochiishi Misaki
- Ochiishinishi
- Ochiai
- Obukaruishi
- Obuchi-numa
- Obuchi
- Ōbō-yama
- Oboro Yama
- Oboro Gawa
- Oboro
- Oboko-dake
- Obirashibe Gawa
- Ōbira-gawa
- Obirachō
- Obira Chō
- Obihiro Shi
- Obihiro Gawa
- Obihiro Dake
- Obihiro
- Obitomi
- Obatazawa
- Ō-ani-gawa
- Oakan Dake
- Nutchi-gawa
- Nusamaichō
- Nunoppe
- Nunokawa
- Nunobe-dake
- Numotoru San
- Numaushi
- Numaura
- Numata
- Numanoue Kōzan
- Numanoue
- Numanosawa
- Numanosawa
- Numanohata-chūō
- Numanohara-yama
- Numamae-misaki
- Numakawa
- Minehama-numata
- Nukkibetsu-yama
- Nukkibetsu Yama
- Nukkibetsu-gawa
- Nukibetsu
- Nukesomanai-yama
- Nukasawa
- Nukanan Gawa
- Nukanai
- Nukabira Yama
- Nukabira Gawa
- Nukabira Gawa
- Nukabira-gensenkyō
- Nuidōishi-yama
- Nubinai Gawa
- Kōtoku
- Nozuka-misaki
- Nozuka Misaki
- Nozuka Gawa
- Nozuka
- Nozuka
- Noushi-gawa
- Notsukashi-yama
- Notsuka
- Notoro Misaki
- Notoro Ko
- Notori
- Noshiro Shi
- Noshiro Kō
- Noshiro Heiya
- Noshiro
- Noshappu Misaki
- Nosappu Misaki
- Nosappu
- Nopporo
- Nonamai