Honshu

Honshu is the largest and most populous island of Japan, comprising the central and eastern part of the archipelago. With an area of about 228,000 square kilometers, it accounts for most of Japan's population and economy. The eastern coast faces the Pacific Ocean, while the western coast borders the Sea of Japan; it is separated from Hokkaido to the north by the Tsugaru Strait. Tokyo, the national capital, sits on the eastern side of the island, alongside several major cities.

Its interior is rugged and mountainous, dominated by the Japanese Alps. The landscape shapes the climate, with humid subtropical lowlands and cooler northern highlands. The Seto Inland Sea lies between Honshu and Shikoku, and major rivers such as Shinano, Tone, and Kiso flow across the island.

Honshu has played a central role in Japanese history and culture. It contains historic capitals such as Kyoto and Nara, and became the seat of the modern state when Tokyo was designated the capital in the 19th century. The island hosts Japan’s institutions, universities, and cultural sites, from ancient temples to contemporary arts and technology.

Economy on Honshu dominates the national economy. The island hosts Japan’s largest cities—Tokyo, Nagoya, and Osaka—whose industries include manufacturing, finance, and technology. Major transport corridors, including the Shinkansen network, connect Honshu with the rest of the country. Haneda and Narita airports serve the area near Tokyo.

Honshu lies in a seismically active region where multiple tectonic plates interact. It was the site of the 2011 Great East Japan Earthquake and tsunami, which caused damage and led to changes in disaster response and safety policy. Ongoing tectonic activity continues to shape the island’s landscape and hazards.