List of Japanese prefectures by population

This is a list of Japanese prefectures by population. For details of administrative divisions of Japan, see Prefectures of Japan.
Figures here are according to the official estimates of Japan as of October 1, 2011, except for the census population held on October 1, 2010. Population is given according to the de jure population concept for enumerating the people. That is, a person was enumerated at the place where they usually lived, and was counted as the population of the area including the place. Ranks are given by the estimated population as of October 1, 2011.
Population before 1920 was calculated based on information of family registries, while door-to-door censuses have been held every 5 years as of October 1 since 1920, except for 1945.
As for prefectural populations before 1945, figures are only given for prefectures that officially constituted Japan Proper or Mainland Japan. Karafuto Prefecture (Southern Sakhalin) was officially incorporated into Japan Proper from March 26, 1943 until the end of the World War II, while Taiwan, the Kwantung Leased Territory, Korea and the South Seas Mandate were treated as exterior territories. At the end of war, Japan lost sovereignty over Southern Sakhalin and the Kuril Islands (part of Hokkaidō, which Japan partly disputes). For the population of the colonies of the former Empire of Japan, see Demographics of Imperial Japan.
Population in the following table is given according to the de jure population concept for enumerating the people.
Population in the following table is given according to the de facto population concept for enumerating the people.
Population in the following tables is given according to the A-type de facto population concept for enumerating the people, based on koseki registration systems.
Population in the following table is given according to the original family registries population concept for enumerating the people, based on koseki registration system.
Several demographic data remain for three urban prefectures,(i.e. Kyōto-fu, Ōsaka-fu and Tōkyō-fu), 266 domains, 40 prefectures and one commission (i.e. Kaitaku-shi only in Hokkaidō) that existed for short time between Meiji Restoration and the Abolition of the han system, though not thoroughly surveyed. Prefectural system was only introduced to imperial territories which the Meiji government gained from Tokugawa shogunate or the revolted feudal lords, while many areas still belonged to local lordship governments. The table below summarizes demographic data from three sources.
Source': (ref.1): Table of households for shi, fu and ken (Meiji-shi-yō).
Statistical data were given as of August 29, 1871 (29th day of the 8th month, Meiji 4) for (1), as of February 2, 1869 (1st day of the 1st month, Meiji 2), for (2) or uncertain for (3), although all these populations seemed to be collected from several koseki populations surveyed in 1869 and 1870. Naotarō Sekiyama noted that the population of Japan as of August, 1870 (7th month, Meiji 3) was 32,794,897 (Kinsei Nihon jinkō-no kenkyū (Study of the Population of Japan in the Early Modern Period) (1948)).
It is quite apparent that the above demographic data contain many textual errors, but could not be corrected because the original unpublished reports preserved at the office of the Ministry of Interior of Japan were burned by a fire after the 1923 Great Kantō earthquake.
For demographic data during the Edo period, see Demographics of Japan before Meiji Restoration.