Those guys come from Dagestan 🤼

This is what chat says: 

The name Sakhalin (Russian: Сахалин) for the large Russian island in the North Pacific originates from a misunderstanding or misapplication of a Manchu term during early European (primarily Russian) exploration and mapping in the 17th–19th centuries.
The root comes from the Manchu language word sahaliyan (ᠰᠠᡥᠠᠯᡳᠶᠠᠨ), meaning “black”. This was part of a longer phrase referring to the nearby Amur River on the mainland: sahaliyan ula (ᠰᠠᡥᠠᠯᡳᠶᠠᠨ ᡠᠯᠠ), literally “Black River” (the Manchu name for the Amur, which shares this etymology with the Chinese name for Heilongjiang province, meaning “Black Dragon River”).
The full Manchu descriptive name for the area or a feature near the Amur’s mouth was sahaliyan ula angga hada (ᠰᠠᡥᠠᠯᡳᠶᠠᠨ ᡠᠯᠠ ᠠᠩᡤᠠ ᡥᠠᡩᠠ), translating roughly to “island/peak at the mouth/estuary of the Black River” (or “craggy rock at the estuary of the Amur”). Russian explorers and mapmakers encountered this term through Manchu or Qing Chinese sources (often in reference to the Amur region or the nearby city of Aigun) and mistakenly applied the shortened form Sahaliyan → Sakhalin to the large island itself lying offshore, rather than to the river or a specific point.
This borrowing entered Russian as Сахали́н (Sakhalín), and it stuck as the standard name. The etymology ultimately traces back further to Proto-Tungusic sakalīn (“black”), reflecting the Tungusic linguistic family that includes Manchu.
For contrast:
	•	The indigenous Ainu (who historically inhabited southern Sakhalin) called it something like Repunmosir or related terms, but their name for it isn’t the source of “Sakhalin”.
	•	The Japanese name during their control of the southern part (1905–1945) was Karafuto (樺太), derived from an Ainu phrase kamuy kar put ya mosir (roughly “the island/land a god created at the mouth/estuary”), often shortened to Karput.
So, while Sakhalin has deep indigenous history with groups like the Ainu, Nivkh (Gilyak), and others, the name “Sakhalin” itself is a European/Russian adaptation of a Manchu description tied to the Amur River—not a direct native name for the island. This is a classic case of cartographic transfer error in colonial-era naming!