Sakhalin (Сахали́н) is an elongated island in Northeast Asia, located just off the southeastern coast of Russia's Khabarovsk Krai, and north of Japan's Hokkaido. A marginal island of the West Pacific, Sakhalin divides the Sea of Okhotsk to its east from the Sea of Japan to its southwest. It is administered as part of Sakhalin Oblast and is the largest island of Russia with an area of . The island has a population of roughly 500,000, the majority of whom are Russians. The indigenous peoples of the island are the Ainu, Oroks, and Nivkhs, who are now present in very small numbers.
The island's name is derived from the Manchu word Sahaliyan (ᠰᠠᡥᠠᠯᡳᠶᠠᠨ). The Ainu people of Sakhalin paid tribute to the Yuan, Ming, and Qing dynasties and accepted official appointments from them. Sometimes the relationship was forced but control from dynasties in China was loose for the most part. Sakhalin was later claimed by both Russia and Japan over the course of the 19th and 20th centuries. These disputes sometimes involved military conflicts and divisions of the island between the two powers. In 1875, Japan ceded its claims to Russia in exchange for the northern Kuril Islands. In 1905, following the Russo-Japanese War, the island was divided, with Southern Sakhalin going to Japan. Russia has held all of the island since seizing the Japanese portion in the final days of World War II in 1945, as well as all of the Kurils. Japan no longer claims any of Sakhalin, although it does still claim the southern Kuril Islands. Most Ainu on Sakhalin moved to Hokkaido, to the south across the La Pérouse Strait, when Japanese civilians were displaced from the island in 1949.
Sakhalin has several names including Karafuto Karafuto; Kuye ; Manchu: ᠰᠠᡥᠠᠯᡳᠶᠠᠨ, Sahaliyan; Orok: Бугата на̄, Bugata nā; Nivkh: Ых-миф, Yh-mif.
The Manchus called it "Sahaliyan ula angga hada" (Island at the Mouth of the Black River) . Sahaliyan, the word that has been borrowed in the form of "Sakhalin", means "black" in Manchu, ula means "river" and sahaliyan ula (, "Black River") is the proper Manchu name of the Amur River.