Hokkaido (hōkī´dō), island (1990 pop. 5,643,515), c.30,130 sq mi (78,040 sq km), N Japan, separated from Honshu island by the Tsugaru Strait and from Sakhalin, Russia, by the Soya Strait. It is the second largest, northernmost, and most sparsely populated of the major islands of Japan. Once called Yezo, it received the name Hokkaido [region of the northern sea] in 1869. Its rugged interior with many volcanic peaks rises to 7,511 ft (2,289 m) in Asahi-dake and, like all of Japan, the island is subject to earthquakes. The Ishikari, second longest river of Japan, traverses W Hokkaido; its valley is an important urban and industrial region. Hokkaido has a humid continental climate and receives much snow. Forests, covering most of the island, are a source of lumber, pulp, and paper (milled in Hokkaido). Coal, iron, and manganese are mined; the Ishikari coal field produces a major part of Japan's supply. Although large areas of the island are unsuited to farming, agriculture is an important occupation. Hokkaido is one of the major fishing centers of the world. The island is the chief winter resort and sports area in Japan; the 1972 Winter Olympics were held there, at Sapporo. Hokkaido's scenic beauty is preserved in several national parks. The population is concentrated largely in the west and southwest. Sapporo, Hakodate, and Otaru are the chief cities. Kushiro is the main port for E Hokkaido.
The island was originally inhabited by Ainu, aborigines of uncertain ancestry. Until 1800 the Ainu outnumbered the Japanese, who had begun (16th cent.) to settle the southwest peninsula; there are now c.16,000 Ainu in Hokkaido. With the Meiji restoration (1868) Japan began the first serious effort to people the island as a means of strengthening the northern frontier. Under a government-sponsored plan to develop the island, Horace Capron, an American agriculturalist, introduced (1872–76) scientific methods of farming. In 1885, Hokkaido was made an administrative unit and was granted a central government. The growth of the railroads helped speed settlement, but despite subsidies, the severe winters discouraged emigration from S Japan. Parts of the island, particularly in the north, are still relatively underpopulated. The completion of the Seikan Tunnel (1988), which carries a rail line connecting Hokkaido and Honshu, has further decreased the isolation of Japan's northernmost island.