;January 1, 2005 •
Sarashina District (更級郡), Nagano (The village of Ooka merged into the city of
Nagano) •
Iinan District (飯南郡), Mie (The towns of Iinan and Iitaka merged with the city of Matsusaka and two towns from Ichishi District to form the city of
Matsusaka) •
Takashima District (高島郡), Shiga (The towns of Adogawa, Imazu, Shinasahi, Takashima, Makino, and the village of Kutsuki merged to form the city of
Takashima) •
Onsen District (温泉郡), Ehime (The town of Nakajima merged into the city of
Matsuyama) •
Kitaamabe District (北海部郡), Ōita (The town of
Saganoseki merged into the city of
Ōita) ;January 11, 2005 •
Kawabe District (河辺郡), Akita (The towns of Kawabe and merged into the city of
Akita) •
Suzuka District (鈴鹿郡), Mie (The town of Seki and the city of Kameyama merged to form the city of
Kameyama) •
Mihara District (三原郡), Hyōgo (The towns of Midori, Seidan, Mihara, and Nandan merged to form the city of
Minamiawaji) •
Uto District (宇土郡), Kumamoto (The towns of Misumi and Shiranuhi merged with three towns from Shimomashiki District to form the city of
Uki) ;February 1, 2005 •
Yoshiki District (吉城郡), Gifu (The town of Kokufu and the village of Kamitakara merged into the city of
Takayama) •
Numakuma District (沼隈郡), Hiroshima (The town of Numakuma merged into the city of
Fukuyama) ;February 7, 2005 •
Mugi District (武儀郡), Gifu (The towns of Mugi, Mugegawa, and the villages of Horado, Kaminoho, and Itadori merged into the city of
Seki) ;February 13, 2005 •
Ena District (恵那郡), Gifu (The town of Sakashita, the villages of Kawaue, Kashimo, the towns of Tsukechi, Fukuoka, and the village of Hirukawa merged into the city of
Nakatsugawa) •
Toyoura District (豊浦郡), Yamaguchi (The towns of Kikukawa, Toyota, Toyoura, and Hōhoku merged with the city of Shimonoseki to form the city of
Shimonoseki) ;February 28, 2005 •
Aso District (安蘇郡), Tochigi (The towns Kuzu and Tanuma merged with the city of Sano to form the city of
Sano) ;March 1, 2005 •
Fugeshi (鳳至郡) and
Suzu (珠洲郡) Districts,
Ishikawa (Merged to form
Hōsu District) •
Shitsuki District (後月郡), Okayama (The town of Yoshii merged into the city of
Ibara) •
Ogi District (小城郡), Saga (The towns of Ogi, Ashikari, Ushizu, and Mikatsuki merged to form the city of
Ogi) •
Kitatakaki District (北高来郡), Nagasaki (The towns of Iimori, Konagai, Takaki, and Moriyama merged with the town of Tarami from Nishisonogi District and the city of Isahaya to form the city of
Isahaya) •
Shimoge District (下毛郡), Ōita (The towns of Honyabakei, Yabakei, Yamakuni, and the village of Sankō merged into the city of
Nakatsu) ;March 3, 2005 •
Minamiamabe District (南海部郡), Ōita (The towns of Ume, Kamae, Kamiura, Tsurumi, Yayoi, and the villages of Naokawa, Honjo, and Yonoutsu merged with the city of Saiki to form the city of
Saiki) ;March 19, 2005 •
Nishikubiki District (西頸城郡), Niigata (The towns of Nose and Oume and the city of Itoigawa merged to form the city of
Itoigawa) ;March 20, 2005 •
Ukiha District (浮羽郡), Fukuoka (The towns of Ukiha and Yoshii merged to form the city of
Ukiha) ;March 22, 2005 •
Kojima District (児島郡), Okayama (The town of Nadasaki merged into the city of
Okayama) •
Kamo District (賀茂郡), Hiroshima (The town of Yamato merged with the town of Hongo from Toyota District, the town of Kui from Mitsugi District, and the city of Mihara to form the city of
Mihara) •
Asa District (厚狭郡), Yamaguchi (The town of San'yō merged with the city of Onoda to form the city of
San'yō-Onoda) •
Ōtsu District (大津郡), Yamaguchi (The towns of Heki, Yuya, and Misumi merged with the city of Nagato to form the city of
Nagato) •
Hita District (日田郡), Ōita (The villages of Maetsue, Nakatsue, Kamitsue, and the towns of Ōyama and Amagase merged into the city of
Hita) ;March 28, 2005 •
Higashikatsushika District (東葛飾郡), Chiba (The town of Shonan merged into the city of
Kashiwa) •
Kaizu District (海津郡), Gifu (The towns of Hirata, Nanno, and Kaizu merged to form the city of
Kaizu) •
Mitsugi District (御調郡), Hiroshima (The town of Mitsugi and Mukaishima merged into the city of
Onomichi) •
Munakata District (宗像郡), Fukuoka (The village of Ōshima merged into the city of
Munakata) ;March 31, 2005 •
Atetsu District (阿哲郡), Okayama (The towns of Ōsa, Shingō, Tetta, and Tessei merged with the city of Niimi to form the city of
Niimi) •
Jōbō District (上房郡), Okayama (The town of Hokubō merged with 8 towns and villages from Maniwa District to form the city of
Maniwa) •
Kōnu District (甲奴郡), Hiroshima (The town of Sōryō merged with 5 towns from Hiba District and the city of Shōbara to form the city of
Shōbara) •
Hiba District (比婆郡), Hiroshima (The towns of Saijō, Tōjō, Kuchiwa, Takano and Hiwa merged with the town of Sōryō from Kōnu District and the city of Shōbara to form the city of Shōbara) •
Usa District (宇佐郡), Ōita (The towns of Innai and Ajimu merged with the city of Usa to form the city of
Usa) •
Ōno District (大野郡), Ōita (The town of Mie, The village of Kiyokawa, the towns of Ogata, Asaji, Ōno, the village of Chitose, and the town of Inukai merged to form the city of
Bungo-ōno) ;April 1, 2005 •
Kurihara District (栗原郡), Miyagi (The towns of Ichihasama, Uguisuzawa, Kannari, Kurikoma, Shiwahime, Semine, Takashimizu, Tsukidate, Wakayanagi, and the village of Hanayama merged to form the city of
Kurihara) •
Tome District (登米郡), Miyagi (The towns of Ishikoshi, Towa, Toyosato, Toyoma, Nakada, Hasama, Minamikata, and Yoneyama merged with the town of Tsuyama from Motoyoshi District to form the city of
Tome) •
Monou District (桃生郡), Miyagi (The towns of Yamoto and Naruse merged to form the city of
Higashimatsushima; the towns of Kahoku, Ogatsu, Kanan, Monou, and Kitakami merged with the town of Oshika from Oshika District and the city of Ishinomaki to form the city of
Ishinomaki) •
Koshi District (古志郡), Niigata (The village of Yamakoshi merged into the city of
Nagaoka) •
Higashikubiki District (東頸城郡), Niigata (The towns of Matsudai and Matsunoyama merged with the city of Tōkamachi and 2 towns and villages from Nakauonuma District to form the city of
Tōkamachi) •
Nakakubiki District (中頸城郡), Niigata (The town of Myōkōkōgen and the village of Myōkō merged into the city of Arai to become the city of
Myōkō) •
Kaminiikawa District (上新川郡), Toyama (The towns of Ōsawano and Ōyama merged with 4 towns and villages from Nei District and the city of Toyama to form the city of
Toyama) •
Nei District (婦負郡), Toyama (The towns of Yatsuo, Fuchu, and the villages of Yamada and Hosoiri merged with two towns from Kaminiikawa District and the city of Toyama to form the city of Toyama) •
Ogasa District (小笠郡), Shizuoka (The towns of Ōsuga and Daitō merged with the city of Kakegawa to form the city of
Kakegawa) •
Haguri District (葉栗郡), Aichi (The town of Kisogawa merged into the city of
Ichinomiya) •
Nakashima District (中島郡), Aichi (The towns of Sofue and Heiwa merged into the city of
Inazawa) •
Higashikamo District (東加茂郡), Aichi (The town of Asuke, the village of Shimoyama, and the towns of Asahi and Inabu merged into the city of
Toyota) •
Asago District (朝来郡), Hyōgo (The towns of Ikuno, Wadayama, Santo, and Asago merged to form the city of
Asago) •
Kinosaki District (城崎郡), Hyōgo (The towns of Kinosaki, Takeno, and Hidaka merged with 2 towns from Izushi District and the city of Toyooka to form the city of
Toyooka; the town of Kasumi merged with the towns of Muraoka and Mikata from Mikata District to form the town of
Kami in
Mikata District) •
Izushi District (出石郡), Hyōgo (The towns of Izushi and Tantō merged with 3 towns from Kinosaki District and the city of Toyooka to form the city of Toyooka) •
Soekami District (添上郡), Nara (The village of Tsukigase merged into the city of
Nara) •
Awa District (阿波郡), Tokushima (The towns of Awa and Ichiba merged with 2 towns from Itano District to form the city of
Awa) •
Naoiri District (直入郡), Ōita (The towns of Ogi, Kujū, and Naoiri merged with the city of Taketa to form the city of
Taketa) ;July 1, 2005 •
Kaijo District (海上郡), Chiba (The towns of Iioka and Unakami merged with the town of Hikata from Katori District and the city of Asahi to form the city of
Asahi) •
Inasa District (引佐郡), Shizuoka (The towns of Inasa, Hosoe, and Mikkabi merged into the city of
Hamamatsu) •
Iwata District (磐田郡), Shizuoka (The towns of Sakuma, Misakubo, and the village of Tatsuyama merged into the city of Hamamatsu) ;August 1, 2005 •
Kibi District (吉備郡), Okayama (The town of Mabi merged into the city of
Kurashiki) ;September 2, 2005 •
Namegata District (行方郡), Ibaraki (The towns of Asou, Kitaura, and Tamatsukuri merged to form the city of
Namegata) ;October 1, 2005 •
Atsuta District (厚田郡), Hokkaido (The village of Atsuta merged into the city of
Ishikari) •
Hamamasu District (浜益郡), Hokkaido (The village of Hamamasu merged into the city of
Ishikari) •
Hiraka District (平鹿郡), Akita (The towns of Masuda, Hiraka, Omonogawa, Ōmori, Jumonji, and the villages of Sannai and Taiyū merged with the city of Yokote to form the city of
Yokote) •
Yuri District (由利郡), Akita (The towns of Nikaho, Konoura, and Kisakata merged to form the city of
Nikaho) •
Nishitagawa District (西田川郡), Yamagata (The town of Atsumi merged with 4 towns and villages from Higashitagawa District and the city of Tsuruoka to form the city of
Tsuruoka) •
Makabe District (真壁郡), Ibaraki (The town of Makabe and the village of Yamato merged with the town of Iwase from Nishiibaraki District to form the city of
Sakuragawa) •
Enuma District (江沼郡), Ishikawa (The town of Yamanaka merged with the city of Kaga to form the city of
Kaga) •
Minamiazumi District (南安曇郡), Nagano (The towns of Toyoshina and Hotaka, and the villages of Misato and Horigane merged with the towns of Akashina from Higashichikuma District to form the city of
Azumino) •
Minamishitara District (南設楽郡), Aichi (The town of Horai and Tsukude merged with the city of Shinshiro to form the city of
Shinshiro) •
Atsumi District (渥美郡), Aichi (The town of Atsumi merged into the city of
Tahara) •
Sakata District (坂田郡), Shiga (The town of Ōmi merged into the city of
Maibara) •
Naka District (那賀郡), Shimane (The towns of Kanagi, Asahi, the village of Yasaka, and the town of Misumi merged with the city of Hamada to form the city of
Hamada) •
Nima District (邇摩郡), Shimane (The towns of Yunotsu and Nima merged with the city of Ōda to form the city of
Ōda) •
Saba District (佐波郡), Yamaguchi (The town of Tokuji merged with three towns from Yoshiki District and the city of Yamaguchi to form the city of
Yamaguchi) •
Yoshiki District (吉敷郡), Yamaguchi (The towns of Aio, Ogori, and Ajisu merged with the town of Tokuji from Saba District and the city of Yamaguchi to form the city of Yamaguchi) •
Nishikunisaki District (西国東郡), Ōita (The village of Ōta merged with the town of Yamaga from Hayami District and the city of Kitsuki to form the city of
Kitsuki) •
Ōita District (大分郡), Ōita (The towns of Yufuin, Shōnai, and Hasama merged to form the city of
Yufu) ;October 11, 2005 •
Kashima District (鹿島郡), Ibaraki (The village of Asahi, the town of Hokota, and the village of Taiyō merged to form the city of
Hokota) ;October 24, 2005 •
Mino District (美嚢郡), Hyōgo (The town of Yokawa merged into the city of
Miki) ;November 1, 2005 •
Higashiyamanashi District (東山梨郡), Yamanashi (The town of Katsunuma and the village of Yamato merged with the city of Enzan to form the city of
Kōshū) •
Imizu District (射水郡), Toyama (The towns of Kosugi, Daimon, Ōshima, and the village of Shimo merged with the city of Shinminato to form the city of
Imizu) •
Nishitonami District (西礪波郡), Toyama (The town of Fukuoka merged with the city of Takaoka to form the city of
Takaoka) ;November 3, 2005 •
Saeki District (佐伯郡), Hiroshima (The towns of Ōno and Miyajima merged into the city of
Hatsukaichi) ;November 7, 2005 •
Ōno District (大野郡), Fukui (The village of Izumi merged into the city of
Ōno) •
Hioki District (日置郡), Kagoshima (The town of Kinpō merged with the city of Kaseda and three towns from Kawanabe District to form the city of
Minamisatsuma) ==2006~==