Most Ainu on Sakhalin moved to Hokkaido, 43 kilometres (27 mi) to the south across the La Pérouse Strait, when Japanese civilians were displaced from the island in 1949.

[citation needed] The Qing dynasty called Sakhalin ‘Kuyedao’ (‘the island of Ainu’) and the indigenous people paid tribute to the Chinese empire.

These include:[14] The Japanese form 樺太 equates to Korean: 화태 Hwangt'ae, an earlier name for the island now superseded by the transcription 사할린 Sahallin.

In response, the Mongols established an administration post at Nurgan (present-day Tyr, Russia) at the junction of the Amur and Amgun rivers in 1263, and forced the submission of the two peoples.

From 1409 to 1411 the Ming established an outpost called the Nurgan Regional Military Commission near the ruins of Tyr on the Siberian mainland, which continued operating until the mid-1430s.

Residents who were required to pay tributes had to register according to their hala (ᡥᠠᠯᠠ, the clan of the father's side) and gashan (ᡤᠠᡧᠠᠨ, village), and a designated chief of each unit was put in charge of district security as well as the annual collection and delivery of fur.

During the reign of the Qianlong Emperor (r. 1735–95), a trade post existed at Delen, upstream of Kiji (Kizi) Lake, according to Rinzo Mamiya.

To obtain Chinese silk, the Ainu fell into debt, owing much fur to the Santan (Ulch people), who lived near the Qing office.

[citation needed] Only with the 1787 expedition of Jean-François de La Pérouse did the island began to resemble something of its true shape on European maps.

[41] In 1855, Russia and Japan signed the Treaty of Shimoda, which declared that nationals of both countries could inhabit the island: Russians in the north, and Japanese in the south, without a clearly defined boundary between.

He spent three months there interviewing thousands of convicts and settlers for a census and published his memoir Sakhalin Island (Russian: Остров Сахалин) of his journey.

In accordance with the Treaty of Portsmouth of 1905, the southern part of the island below the 50th parallel north reverted to Japan, while Russia retained the northern three-fifths.

[citation needed] In response to the United States opening of Japan by Commodore Matthew C. Perry in 1853 and, later, the subsequent signing of the Convention of Kanagawa on March 31, 1854, Tsar Nicholas I, who was personally involved in the "Sakhalin issue", in April 1853 ordered the Russian-American Company (RAC) to immediately occupy the Sakhalin Island and begin colonization by constructing two redoubts armed with cannons on the western and southern coasts of the island.

[44] On September 20, 1853, the RAC ship "Emperor Nikolai I" (Russian: РАК «Император Николай I») under the command of skipper Martin Fyodorovich Klinkowström (Russian: под командой шкипера Клинковстрём) and under the general guidance of Captain Nevelskoy arrived at Tomari-Aniva on Aniva Bay, not far from the main Japanese settlement on the island, and put ashore men and materials to form a military outpost.

On April 18, 1869, Tsar Alexander II approved the "Regulations of the Committee on the Arrangement of Hard Labor" (Russian: «Положение Комитета об устройстве каторжных работ») which formed the legal basis for Sakhalin Island to be a penal colony.

[45][46] In 1920, during the Siberian Intervention, Japan again occupied the northern part of the island, returning it to the Soviet Union in 1925 after the Treaty of Beijing was signed on January 20, 1925.

[49][50][51] In August 1945, after repudiating the Soviet–Japanese Neutrality Pact, the Soviet Union invaded southern Sakhalin, an action planned secretly at the Yalta Conference.

[62] Crystalline rocks crop out at several capes; Cretaceous limestones, containing an abundant and specific fauna of gigantic ammonites, occur at Dui on the west coast; and Tertiary conglomerates, sandstones, marls, and clays, folded by subsequent upheavals, are found in many parts of the island.

The clays, which contain layers of good coal and abundant fossilized vegetation, show that during the Miocene period, Sakhalin formed part of a continent which comprised north Asia, Alaska, and Japan, and enjoyed a comparatively warm climate.

According to the 1897 census, Sakhalin had a population of 28,113, of which 56.2% were Russians, 8.4% Ukrainians, 7.0% Nivkh, 5.8% Poles, 5.4% Tatars, 5.1% Ainu, 2.82% Oroks, 0.95% Germans, 0.81% Japanese, with the non-indigenous people living mainly from agriculture, or being convicts or exiles.

[70][failed verification] Precipitation is heavy, owing to the strong onshore winds in summer and the high frequency of North Pacific storms affecting the island in the autumn.

In contrast to interior east Asia with its pronounced summer maximum, onshore winds ensure Sakhalin has year-round precipitation with a peak in the autumn.

The underwoods abound in berry-bearing plants (e.g. cloudberry, cranberry, crowberry, red whortleberry), red-berried elder (Sambucus racemosa), wild raspberry, and Spiraea.

The bird population is made-up of mostly the common eastern Siberian forms, but there are some endemic or near-endemic breeding species, notably the endangered Nordmann's greenshank (Tringa guttifer) and the Sakhalin leaf warbler (Phylloscopus borealoides).

Numerous cetaceans visit the sea coast, including the endangered Western Pacific gray whale,[71] for which the waters off of Sakhalin are their only known feeding ground, thus being a vitally important region for their population's longevity.

Besides the main network run by the Russian Railways, until December 2006 the local oil company (Sakhalinmorneftegaz) operated a corporate narrow-gauge 750 mm (2 ft 5+1⁄2 in) line extending for 228 kilometers (142 mi) from Nogliki further north to Okha (Узкоколейная железная дорога Оха – Ноглики).

In 2000, the Russian government revived the idea, adding a suggestion that a 40-km (25 mile) long bridge could be constructed between Sakhalin and the Japanese island of Hokkaidō, providing Japan with a direct connection to the Eurasian railway network.

The cost will include an estimated US$1 billion to upgrade the island's infrastructure: roads, bridges, waste management sites, airports, railways, communications systems, and ports.

Russia is in the process of building a 220 km (140 mi) pipeline across the Tatar Strait from Sakhalin Island to De-Kastri terminal on the Russian mainland.

The cost overruns (at least partly due to Shell's response to environmental concerns), are reducing the share of profits flowing to the Russian treasury.