Prefectural border changes
This list may be incomplete, some smaller changes through cross-prefectural municipal mergers/transfers of neighbourhoods/border corrections may be missing. Changes in Tokyo's coastline are not included.
- 1871/72 – Abolition of feudal domains and first wave of prefectural mergers: Major parts of Shinagawa, Kosuge and Urawa Prefectures, covering the ancient Musashi Province Districts Ebara and Toshima and parts of Tama, Adachi and Katsushika become part of Tokyo.
- 1871/72 (eleventh month of Meiji 4/1871 (?)) – The Setagaya exclave (around present-day Setagaya in Setagaya Ward/"City") of Hikone Prefecture comprising 20 pre-modern Villages in the Ebara and Tama Districts is merged into Tokyo.
- 1878 – The Izu Islands (no district, Izu Province) are transferred from Shizuoka to Tokyo.
- 1880 – The Ogasawara Islands (no district, no province), previously under direct Home Ministry administration, are transferred to Tokyo.
- 1893 – The "three Tama" (san-Tama) [Districts], North Tama, South Tama and West Tama – the three western sections of ancient Tama district, Musashi province – comprising 91 Towns and Villages are transferred from Kanagawa to Tokyo.
- 1907 – Hōya village in North Adachi (before 1896: Niikura) district, Saitama is transferred to North Tama District, Tokyo.
- 1926 – The neighbourhood of Ukima from Yokozone Village [in North Adachi District], Saitama is transferred to Iwabuchi Town [in North Toshima District], Tokyo. (The remainder of Yokozone Village became part of Kawaguchi City in 1933.)
- 1958 – The majority of Moto-Sayama Village [in Iruma District], Saitama is merged into Mizuho Town [in West Tama], Tokyo. (The remainder of Moto-Sayama is simultaneously merged into Musashi Town [in Iruma district], Saitama.)
This list is incomplete, most mergers are missing.
- 1917 – Hachiōji Town became an [independent] City, leaving Minamitama District.
- 1920 – Naitō-Shinjuku Town from Toyotama district is merged into Tokyo City where it becomes part of Yotsuya Ward.
- 1932 (establishment of Dai-Tōkyō-shi, "Greater Tokyo City") – 82 towns and villages were merged into Tokyo City and consolidated into 20 new wards.
- 1936 – The villages of Kinuta and Chitose were merged into Tokyo City and integrated into Setagaya Ward.
- 1941 – Komiya town was merged into Hachiōji city.
- In 1943 - Tokyo City (Tōkyō-shi) was abolished, and the government of the larger Tokyo Prefecture (Tōkyō-fu), henceforth the Tokyo Metropolis (Tōkyō-to), assumed the direct administration of the former city. Since 1943, no city in Japan has had the name Tokyo.
- March 1947 - The 35 wards of former Tokyo city were consolidated into 22 wards.
- May 1947 – The 22 wards were transformed into quasi-municipal special wards.
- August 1947 – The special ward of Nerima was split off from Itabashi.
- On 1955 – the villages of Hirai and Ōguno (both from Nishitama District) were merged to create the village of Hinode.
- On 1955 – the old city of Hachiōji absorbed the villages of Yokoyama, Moto-Hachiōji, Ongata, Kawaguchi, Kasumi and Yui (all from Minamitama District) to create new and expanded city of Hachiōji.
- On 1956 – the old village of Miyake absorbed the villages of Tsubota and Ako (all from Miyake Subprefecture) to create new and expanded village of Miyake.
- On 1958 – the former Machida town and the villages of Tadao, Tsurukawa and Sakai (all from Minamitama District) were merged to create and new establish the city of Machida.
- On 1959 – the village of Asakawa (from Minamitama District) were merged into expanded city of Hachiōji.
- On 1963 – the old city of Tachikawa absorbed the town of Sunagawa (from Kitatama District) to create new and expanded city of Tachikawa.
- On 1964 - the village of Yugi (from Minamitama District) were merged into expanded city Hachiōji.
- On 1995 - the city of Akigawa merged with the town of Itsukaichi (from Nishitama District) were merged to create the city of Akiruno.
- On January 21, 2001 - the cities of Hōya and Tanashi were merged to create the city of Nishitōkyō.