Which of Japan's four main islands has the smallest population?

Shikoku is the smallest (225 km or 139.8 mi long and between 50 and 150 km or 31.1 and 93.2 mi wide) and least populous (3,815,000 as of 2015) of the four main islands of Japan, located south of Honshu and east of the island of Kyushu. The current name refers to the four former provinces that made up the island: Awa, Tosa, Sanuki, and Iyo.

Shikoku island, comprising Shikoku and its surrounding islets, covers about 18,800 square kilometres (7,259 sq mi) and consists of four prefectures: Ehime, Kagawa, Kōchi, and Tokushima. Across the Inland Sea lie Wakayama, Osaka, Hyōgo, Okayama, Hiroshima, and Yamaguchi Prefectures on Honshu. To the west lie Ōita and Miyazaki Prefectures on Kyushu.

Island Population

Honshū 104,000,000 (2010)

Kyūshū 13,200,000 (2010)

Hokkaidō 5,383,579 (2015)