The Small Sea Strait is a strait

Strait

A strait or straits is a narrow, typically navigable channel of water that connects two larger, navigable bodies of water. It most commonly refers to a channel of water that lies between two land masses, but it may also refer to a navigable channel through a body of water that is otherwise not...

 of Lake Baikal

Lake Baikal

Lake Baikal is the world's oldest at 30 million years old and deepest lake with an average depth of 744.4 metres.Located in the south of the Russian region of Siberia, between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast, it is the most voluminous freshwater lake in the...

, Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

. It separates the Olkhon Island from the Western shore of Baikal. Its length is about 8 km, width is about 1.7 km and maximal depth is 200m.

The Small Sea is known to be rich in fish. Its waters are heated up to 20-25 Celsius during summer.

The Sarma River

Sarma River

Sarma is a river in Irkutsk Oblast, Russia. It runs from the Baikal Range into the Small Sea Strait of Lake Baikal.The valley and estuary of Sarma is the source of the strongest of Baikal winds, the Sarma wind. Its speed may exceed 40 meters per second....

 flows into the Small Sea.

The strait is a result of millions of years of tectonic movement, resulting in the hollowing of the channel between the land and the block of stone forming the Olkhon Island.