Hokkaidō is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel.
The largest city on Hokkaidō is its capital, Sapporo, which is also its only ordinance-designated city. Sakhalin lies about 43 kilometers to the north of Hokkaidō, and to the east and northeast are the Kuril Islands, which are administered by Russia, though the four most southerly are claimed by Japan. Hokkaidō was formerly known as Ezo, Yezo, Yeso, or Yesso.Although there were Japanese settlers who ruled the southern tip of the island since the 16th century, Hokkaido was considered foreign territory that was inhabited by the indigenous people of the island, known as the Ainu people.
Wikipedia https://en.wikipedia.org/wiki/Hokkaido
Coordinates 43°3'42.97" N 141°21'15.453" E