The Ishikari coal basin lies in the tertiary mountains of the mining region of Sorachi, east of the Ishikari Plain in central Hokkaido. These coal veins contain the largest quantity of coal of Japan. Because of its late discovery the historical role of the coalfield could not be compared with that of the Chikuho coalfield, but its economic importance since the Japanese industrial revolution is comparable with that of the southern Chikuhō coalfield.

Hokkaido is the second-largest island of Japan 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.