Japan’s main island holds four-fifths of the nation’s people
Honshu—“main province”—is Japan’s largest island, seventh-largest on Earth, and second-most populous after Java. As of 2025 about 100.7 million residents, 81.9% of Japan’s people, crowd its coasts and plains, with roughly thirty percent in Greater Tokyo on the Kantō Plain.
Older names include Akitsushima, dragonfly island, and Hondo, mainland. It stretches roughly 1,300 kilometres, varies from 50 to 230 kilometres across and covers 227,960 square kilometres, a little more than Britain, with 10,084 kilometres of shoreline. Reclamation and tectonic uplift keep adding land. Mount Fuji, an active volcano of 3,776 metres, tops the island, Lake Biwa is Japan’s biggest lake and the Shinano its longest river, while the Japanese Alps run from the Sea of Japan to the Pacific.
Forty active volcanoes and constant quakes come with a Ring of Fire address. The Great Kantō earthquake wrecked Tokyo in September 1923. In March 2011 a magnitude 9.0–9.1 shock offshore shifted the northeast by up to 5.3 metres, raised tsunami waves as high as 40.5 metres, killed 19,759 people and triggered three reactor meltdowns at Fukushima Daiichi. Moist air off the Sea of Japan striking the mountains makes Niigata, Toyama and Nagano some of the snowiest inhabited places anywhere.
Stone Age hunters from Northeast Asia arrived at least 37,000 years ago, probably tracking ice-age game, and left blades like Siberian ones. The Jōmon culture, roughly 14,000 to 300 BCE, followed with cord-marked pots and dogū figurines. Kyoto, Nara and Kamakura all served as capitals, and samurai from Chōshū in the far west helped topple the shogunate in the 1868 Meiji Restoration.
The island produces around US$3.5 trillion, over 80 percent of national output, with the Keihin, Hanshin and Chūkyō industrial zones strung along its southern coast. Tōhoku holds almost a quarter of Japan’s rice paddies, Chiba leads peanut farming, and most tea and silk come from here, along with modest oil in Niigata, Yamagata and Akita. The Tokaido Shinkansen, opened between Tokyo and Shin-Ōsaka in 1964, is the world’s oldest high-speed line. Bridges and the Seikan and Kanmon tunnels tie Honshu to Shikoku, Hokkaido and Kyushu, and its 34 prefectures include Tokyo, home to 14,246,219 people.
Source: Honshu
