Kuril Islands (kyŏŏr´ēl, kŏŏrēl´) or Kuriles (kyŏŏr´ēlz, kyŏŏrēlz´), Jap. Chishima-Retto, Rus. Kurilskiye Ostrova, island chain, c.6,020 sq mi (15,590 sq km), Sakhalin region, E Russia. They stretch c.775 mi (1,250 km) between S Kamchatka Peninsula and NE Hokkaido, Japan, and separate the Sea of Okhotsk from the Pacific Ocean. There are 30 large and numerous small islands; Iturup is the largest. Atlasova volcano (7,674 ft/2,339 m) on Atlasova Island is the highest point of the chain. The islands are mainly of volcanic origin. Active volcanoes are present and earthquakes are frequent. The low temperature, high humidity, and persistent fog make the islands unpleasant for human habitation. There are, however, communities engaged in sulfur mining, hunting, and fishing. Significant deposits of petroleum, magnesium, titanium, and rhenium have been identified.
In the 18th cent. both Russians and Japanese claimed the islands (they are still known in Japan as the Northern Territories). In 1875, Japan gave up Sakhalin in return for Russian withdrawal from the Kuriles, and the Japanese held the islands until the end of World War II. The Yalta Conference ceded the islands to the USSR, and Soviet forces occupied the chain in Sept., 1945. Japan has challenged the Soviet (after 1991, Russian) right to the Kuriles, and demanded the return of the four southernmost islands, which had been treated as part of Hokkaido prior to World War II. The failure to resolve the impasse has been a major stumbling block in Russo-Japanese relations since the end of the war, leading at times to tensions.