Hokkaidō (help·info) (北海道?, literally "North Sea Circuit"), formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island and the largest, northernmost of its 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaidō from Honshū, although the two islands are connected by the underwater Seikan Tunnel. The largest city on Hokkaidō is its capital, Sapporo, which is also its only ordinance-designated city.
Sōunkyō, a gorge in the Daisetsu-zan Volcanic Area.Satellite image of Hokkaidō.The Oyashio Current colliding with the Kuroshio Current off the coast of Hokkaidō. When two currents collide, they create eddies. Phytoplankton growing in the surface waters become concentrated along the boundaries of these eddies, tracing out the motions of the water.The island of Hokkaidō is located at the north end of Japan, near Russia, and has coastlines on the Sea of Japan, the Sea of Okhotsk, and the Pacific Ocean. The center of the island has a number of mountains and volcanic plateaus, and there are coastal plains in all directions. Major cities include Sapporo and Asahikawa in the central region and the port of Hakodate facing Honshū.
The governmental jurisdiction of Hokkaidō incorporates several smaller islands, including Rishiri, Okushiri Island, and Rebun. (By Japanese reckoning, Hokkaidō also incorporates several of the Kuril Islands.) Because the prefectural status of Hokkaidō is denoted by the dō in its name, it is rarely referred to as "Hokkaidō Prefecture", except when necessary to distinguish the governmental entity from the island.
The island ranks 21st in the world by area. It is 3.6% smaller than the island of Ireland while Hispaniola is 6.1% smaller than Hokkaidō. By population it ranks 20th, between Ireland and Sicily. Hokkaidō's population is 4.7% less than that of the island of Ireland, and Sicily's is 12% lower than Hokkaidō's.