A district of Japan is dissolved when all towns or villages in the district become cities or are merged into the city. The following is a list of dissolved districts of Japan. The date shown is the day the district was dissolved (i.e. the district was active until that date) and the reason why the district was dissolved is also shown. Before Edo period Unknown Suruga District (駿河郡), Suruga, Tokaido (Renamed to Suntō District) Unknown Kudara District (百済郡), Settsu, (Merged into either Higashinari and Sumiyoshi Districts) Unknown Nuttari District (沼垂郡), Echigo, Hokurikudo (Merged into Kanbara District) Unknown Tajihi District (百済郡), Kawachi, (Split into Tanboku, Tannan and Yakami Districts) Sengoku Era Hinai District (比内郡), Mutsu, Tozando (Merged into Akita District in Dewa Province) Sengoku Era Ogashima District (小鹿島郡), Dewa, Tozando (Merged into Akita District) Sengoku Era Yamada District (山田郡), Owari, Tokaido (Split and merged into Kasugai and Aichi Districts) Early Edo Period Hanawa (鼻和郡), Hiraka (平賀郡), and Inaka (田舎郡) Districts, Mutsu, Tozando (Merged to form Tsugaru District) Early Edo Period Hiyama District (檜山郡), Dewa, Tozando (Renamed to Yamamoto District) Early Edo Period Toshima District (豊島郡), Dewa, Tozando (Renamed to Kawabe District) Early Edo Period Yamamoto District (山本郡), Dewa, Tozando (Renamed to Senboku District) Early Edo Period Yuza District (遊佐郡), Dewa, Tozando (Renamed to Akumi District) Early Edo Period Kujibiki District (櫛引郡), Dewa, Tozando (Merged into Tagawa District) Edo Period Shikama District (色麻郡), Mutsu, Tozando (Merged into Kami District) 1634 Nukanobe District (糠部郡), Mutsu, Tozando (Split into Kita, Sannohe, Ninohe, and Kunohe Districts) 1700 Noto District (能登郡), Noto, Hokurikudo (Renamed to Kashima District) 1700 Kaga District (加賀郡), Kaga, Hokurikudo (Renamed to Kahoku District) Edo Period Mashiki District (益城郡), Higo, Saikaido (Split into Kamimashiki and Shimomashiki Districts) 1868 to 1895 Tōhoku 1878 Kita District (北郡), Mutsu (Split into Kamikita and Shimokita Districts in Aomori Prefecture) 1878 Tsugaru District (津軽郡), Mutsu (Split into Kitatsugaru, Minamitsugaru, Higashitsugaru, Nishitsugaru and Nakatsugaru Districts in Aomori Prefecture) 1878 Hei District (閉伊郡), Rikuchū (Split into Kitahei, Minamihei, Higashihei, Nishihei and Nakahei Districts in Iwate Prefecture) 1878 Iwai District (磐井郡), Rikuchū (Split into Higashiiwai and Nishiiwai Districts in Iwate Prefecture) 1878 Kunohe District (九戸郡), Rikuchū (Split into Kitakunohe and Minamikunohe Districts in Iwate Prefecture) 1878 Waga District (和賀郡), Rikuchū (Split into Higashiwaga and Nishiwaga Districts in Iwate Prefecture) 1878 Akita District (秋田郡), Ugo (Split into Kitaakita and Minamiakita Districts in Akita Prefecture) 1878 Tagawa District (田川郡), Uzen (Split into Higashitagawa