Honshū (help·info) (本州, literally "Main State") is the largest island of Japan, called the Mainland; it is south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Strait. It is the seventh largest island, and the second most populous island in the world after Java (see the list of islands by area, population).
The island is roughly 1,300 km long and ranges from 50 to 230 km wide, and its total area is 230,500 km², around 60% of the total area of Japan. It is larger than the island of Great Britain, and slightly larger than the state of Minnesota. Honshū has 5,450 km of coastline.
Mountainous and volcanic, Honshū has frequent earthquakes (the Great Kantō earthquake heavily damaged Tokyo in September 1923); the highest peak is the active volcano Mount Fuji at 3,776 m, which makes it the world's 7th highest island. There are many rivers, including the Shinano River, Japan's longest. The climate is highly variable from the cool north to the subtropical south.
It has a population of 98,352,000 (as of 1990; in 1975 it was 89,101,702), mostly concentrated in the available lowlands, notably in the Kantō plain where 25% of the total population reside in the Greater Tokyo Area, which includes Tokyo and Yokohama, Kawasaki, Saitama and Chiba cities. Other cities include Kyoto, Osaka, Nagoya, Kobe, Hiroshima and Sendai. The island is nominally divided into five regions and contains 34 prefectures, including metropolitan Tokyo.
The regions are Chūgoku (western), Kansai (southern, east of Chūgoku), Chūbu (central), Kantō (eastern), and Tōhoku (northern).
Historical centers are also present, such as Kyoto, Nara, and Kamakura.
The island also includes important agricultural regions. Niigata is noted as an important producer of rice. The Kantō and Nōbi plains produce rice and vegetables. Yamanashi is a major fruit-growing area, and Aomori is famous for its apples.
A mountain range runs along the length of Honshū from end to end. In addition to Mt. Fuji, the Japanese Alps are features of Honshū. The mountains are responsible for a marked difference in climate between the eastern or southern (Pacific or Inland Sea coast) side, and the western or northern (Sea of Japan coast) side.
The prefectures are:
Honshū is connected to the islands of Hokkaidō, Kyūshū and Shikoku by tunnels or bridges. Three new bridge systems have been built across the islands of the Inland Sea between Honshū and Shikoku (Akashi-Kaikyo Bridge and the Ohnaruto Bridge; Shin-Onomichi Bridge, Innoshima Bridge, Ikuchi Bridge, Tatara Bridge, Ohmishima Bridge, Hakata-Ohshima Bridges, and the Kurushima-Kaikyo Bridge; Shimotsui-Seto Bridge, Hitsuishijima Bridge, Iwakurojima Bridge, Yoshima Bridge, Kita Bisan-Seto Bridge, and the Minami Bisan-Seto Bridge), and the Seikan Tunnel connects Honshū with Hokkaidō.

Chūgoku region — Hiroshima-ken, Okayama-ken, Shimane-ken, Tottori-ken, Yamaguchi-ken.
Kansai — Hyōgo-ken, Kyoto-fu, Mie-ken, Nara-ken, Osaka-fu, Shiga-ken, Wakayama-ken.
Chūbu — Aichi-ken, Fukui-ken, Gifu-ken, Ishikawa-ken, Nagano-ken, Niigata-ken, Toyama-ken, Shizuoka-ken, Yamanashi-ken.
Kantō — Chiba-ken, Gunma-ken, Ibaraki-ken, Kanagawa-ken, Saitama-ken, Tochigi-ken, Tokyo-to.
Tōhoku — Akita-ken, Aomori-ken, Fukushima-ken, Iwate-ken, Miyagi-ken, Yamagata-ken.