
Sakhalin is an island in the northern Pacific Ocean. Sakhalin is Russia's largest island, and its population of 497,973 (2010) consisted mostly of ethnic Russians and a few Koreans.
Sakhalin was originally inhabited by the Ainu in the south, the Oroks in the center, and the Nivkhs in the north. In 1264, the Mongol Empire made its first attempt to subjugate Sakhalin, which was conquered by the Yuan dynasty in 1308; the Ainu were the last to surrender. In 1679, the Japanese began an early colonization attempt on Sakhalin, and the Qing dynasty also laid claim to the islands. For several years, Sakhalin was regarded as a peninsula and a part of the Japanese mainland of Honshu (as was Hokkaido). After 1849, Russian settlers began to arrive on the islands, defying the Qing and Japanese claims to the island. The Russians set up coal mines, administration facilities, schools, and churches on the island, which was divided between the Russian north and the Japanese south in an 1856 treaty. In 1860, the Qing dynasty was forced to cede all of its claims to the island; Japan later ceded Sakhalin to Russia in 1875 in exchange for complete control over the Kuril Islands to the south. In 1905, the Japanese invaded Sakhalin during the Russo-Japanese War and gained two-fifths of the island (in the south). From 1920 to 1925, during the Russian Civil War, Japan occupied the northern three-fifths, later returning them to the Russian SFSR. In 1945, the Soviet Union conquered Sakhalin at the end of World War II, and 100,000 of the 400,000 residents of the island were evacuated to Japan when the Soviets conquered the island. Tens of thousands of Sakhalin Koreans and their Japanese spouses remained on the island, even as the majority of the other Koreans and Japanese were deported.