Kantō region in the context of "Keihin region"

Tokyo, officially the Tokyo Metropolis, is the capital and most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is one of the most populous urban areas in the world. The Greater Tokyo Area, which includes Tokyo and parts of six neighboring prefectures, is the most populous metropolitan area in the world, with 41 million residents as of 2024.

Lying at the head of Tokyo Bay, Tokyo is part of the Kantō region, on the central coast of Honshu, Japan's largest island. It is Japan's economic center and the seat of the Japanese government and the Emperor of Japan. The Tokyo Metropolitan Government administers Tokyo's central 23 special wards, which formerly made up Tokyo City; various commuter towns and suburbs in its western area; and two outlying island chains, the Tokyo Islands. Although most of the world recognizes Tokyo as a city, since 1943 its governing structure has been more akin to that of a prefecture, with an accompanying Governor and Assembly taking precedence over the smaller municipal governments that make up the metropolis. Special wards in Tokyo include Chiyoda, the site of the National Diet Building and the Tokyo Imperial Palace; Shinjuku, the city's administrative center; and Shibuya, a hub of commerce and business.

The Greater Tokyo Area is the most populous metropolitan area in the world, consisting of the Kantō region of Japan (including Tokyo Metropolis and the prefectures of Chiba, Gunma, Ibaraki, Kanagawa, Saitama, and Tochigi) as well as the prefecture of Yamanashi of the neighboring Chūbu region. In Japanese, it is referred to by various terms, one of the most common being Capital Region (首都圏, Shuto-ken).

As of 2016, the United Nations estimates the total population at 38,140,000. It covers an area of approximately 13,500 km (5,200 mi), giving it a population density of 2,642 people/km. It is the second-largest single metropolitan area in the world in terms of built-up or urban function landmass at 8,547 km (3,300 mi), behind only the New York City metropolitan area at 11,642 km (4,495 mi). With over US$2 trillion in GDP, Tokyo remains the second-largest metropolitan economy in the world, also behind New York.

Tokyo Bay (東京湾, Tōkyō-wan) is a bay located in the southern Kantō region of Japan spanning the coasts of Tokyo, Kanagawa Prefecture, and Chiba Prefecture, on the southern coast of the island of Honshu. Tokyo Bay is connected to the Pacific Ocean by the Uraga Channel. The Tokyo Bay region is the most populous and the largest industrialized area in Japan.

Japan is often divided into regions, each containing one or more of the country's 47 prefectures at large. Sometimes, they are referred to as "blocs" (ブロック, burokku), or "regional blocs" (地域ブロック, chiiki burokku) as opposed to more granular regional divisions. They are not official administrative units, though they have been used by government officials for statistical and other purposes since 1905. They are widely used in, for example, maps, geography textbooks, and weather reports, and many businesses and institutions use their home regions in their names as well, for example Kyushu National Museum, Kinki Nippon Railway, Chūgoku Bank, and Tōhoku University.

One common division groups the prefectures into eight regions. In this arrangement, of the four main islands of Japan, Hokkaidō, Honshu, Shikoku, and Kyūshū, each form their own region, with Kyūshū also including the Satsunan Islands. The largest island, Honshū, is split into five regions. Okinawa Prefecture is usually considered part of Kyūshū, but it is sometimes treated as its own ninth region.

Chiba Prefecture (千葉県, Chiba-ken; Japanese pronunciation: [tɕiꜜ.ba, tɕi.baꜜ, tɕi.baꜜkeɴ]) is a prefecture of Japan located in the Kantō region of Honshu. Chiba Prefecture has a population of 6,278,060 (1 June 2019) and has a geographic area of 5,157 km (1,991 sq mi). Chiba Prefecture borders Ibaraki Prefecture to the north, Saitama Prefecture to the northwest, and Tokyo to the west.

Chiba is the capital and largest city of Chiba Prefecture, with other major cities including Funabashi, Matsudo, Ichikawa and Kashiwa. Chiba Prefecture is located on Japan's eastern Pacific coast to the east of Tokyo, and is part of the Greater Tokyo Area, the most populous metropolitan area in the world. Chiba Prefecture largely consists of the Bōsō Peninsula, which encloses the eastern side of Tokyo Bay and separates it from Kanagawa Prefecture. Chiba Prefecture is home to Narita International Airport, the Tokyo Disney Resort, and the Keiyō Industrial Zone.

Gunma Prefecture (群馬県, Gunma-ken; Japanese pronunciation: [ɡɯꜜm.ma, ɡɯm.maꜜ.keɴ]) is a landlocked prefecture of Japan located in the Kantō region of Honshu. Gunma Prefecture has a population of 1,937,626 (1 October 2019) and has a geographic area of 6,362 square kilometres (2,456 sq mi). Gunma Prefecture borders Niigata Prefecture and Fukushima Prefecture to the north, Nagano Prefecture to the southwest, Saitama Prefecture to the south, and Tochigi Prefecture to the east.

Maebashi is the capital and Takasaki is the largest city of Gunma Prefecture, with other major cities including Ōta, Isesaki, and Kiryū. Gunma Prefecture is one of only eight landlocked prefectures, located on the northwestern corner of the Kantō Plain with 14% of its total land being designated as natural parks.

Ibaraki Prefecture (茨城県, Ibaraki-ken; Japanese pronunciation: [i.baꜜ.ɾa.kʲi, i.ba.ɾa.kʲi̥ꜜ.keɴ, i.ba.ɾaꜜ.kʲi̥.keɴ]) is a prefecture of Japan located in the Kantō region of Honshu. Ibaraki Prefecture has a population of 2,828,086 (1 July 2023) and has a geographic area of 6,097.19 square kilometres (2,354.14 square miles). Ibaraki Prefecture borders Fukushima Prefecture to the north, Tochigi Prefecture to the northwest, Saitama Prefecture to the southwest, Chiba Prefecture to the south, and the Pacific Ocean to the east.

Mito, the capital, is the largest city in Ibaraki Prefecture. Other major cities include Tsukuba, Hitachi, and Hitachinaka. Ibaraki Prefecture is located on Japan's eastern Pacific coast to the northeast of Tokyo, and is part of the Greater Tokyo Area, the most populous metropolitan area in the world. Ibaraki Prefecture features Lake Kasumigaura, the second-largest lake in Japan; the Tone River, Japan's second-longest river and largest drainage basin; and Mount Tsukuba, one of the most famous mountains in Japan. Ibaraki Prefecture is also home to Kairaku-en, one of the Three Great Gardens of Japan, and is an important center for the martial art of Aikido.

Kanagawa Prefecture (神奈川県, Kanagawa-ken; Japanese pronunciation: [ka.naꜜ.ɡa.wa, -ŋa.wa, -na.ɡa.waꜜ.keɴ, -ŋa.waꜜ-]) is a prefecture of Japan located in the Kantō region of Honshu. Kanagawa Prefecture is the second-most populous prefecture of Japan at 9,221,129 (1 April 2022) and third-densest at 3,800 inhabitants per square kilometre (9,800/sq mi). Its geographic area of 2,415 km (932 sq mi) makes it fifth-smallest. Kanagawa Prefecture borders Tokyo to the north, Yamanashi Prefecture to the northwest and Shizuoka Prefecture to the west.

Yokohama is the capital and largest city of Kanagawa Prefecture and the second-largest city in Japan, with other major cities including Kawasaki, Sagamihara, and Fujisawa. Kanagawa Prefecture is located on Japan's eastern Pacific coast on Tokyo Bay and Sagami Bay, separated by the Miura Peninsula, across from Chiba Prefecture on the Bōsō Peninsula. Kanagawa Prefecture is part of the Greater Tokyo Area, the most populous metropolitan area in the world, with Yokohama and a number of its cities being major commercial hubs and southern suburbs of Tokyo. Kanagawa Prefecture was the political and economic center of Japan during the Kamakura period when Kamakura was the de facto capital and largest city of Japan as the seat of the Kamakura shogunate from 1185 to 1333. Kanagawa Prefecture is a popular tourist area in the Tokyo region, with Kamakura and Hakone being two popular side trip destinations.

Saitama Prefecture (埼玉県, Saitama-ken; Japanese pronunciation: [saꜜi.ta.ma, sai.ta.maꜜ.keɴ]) is a landlocked prefecture of Japan located in the Kantō region of Honshu. Saitama Prefecture has a population of 7,338,536 (January 1, 2020) and has a geographic area of 3,797 km (1,466 sq mi). Saitama Prefecture borders Tochigi Prefecture and Gunma Prefecture to the north, Nagano Prefecture to the west, Yamanashi Prefecture to the southwest, Tokyo to the south, Chiba Prefecture to the southeast, and Ibaraki Prefecture to the northeast.

Saitama is the capital and largest city of Saitama Prefecture, with other major cities including Kawaguchi, Kawagoe, and Tokorozawa.