The Circumbaikal Highway (Around Baikal Highway, Round Baikal Highway) was part of the Main Siberian Postal Highway (главный сибирский почтовый тракт). It started from Irkutsk

Irkutsk

Irkutsk is a city and the administrative center of Irkutsk Oblast, Russia, one of the largest cities in Siberia. Population: .-History:In 1652, Ivan Pokhabov built a zimovye near the site of Irkutsk for gold trading and for the collection of fur taxes from the Buryats. In 1661, Yakov Pokhabov...

, went along the Irkut River

Irkut River

Irkut is a river in the Buryat Republic and Irkutsk Oblast of Russia; Angara's left tributary. The length of the river is . The area of its basin is . The Irkut River freezes up in late October - mid-November and stays icebound until late April - early May. The city of Irkutsk is located at the...

, further southwards around 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...

 (hence the name) to the village of Kultushnoye (now Kultuk

Kultuk

Kultuk is an urban locality in Slyudyansky District of Irkutsk Oblast, Russia, located on the southwestern tip of Lake Baikal. Population: It was established in 1647....

). At Kultushnoye the road turned south and went into Mongolia

Mongolia

Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

. The initial run of the road (up to Kutlushnoye, 93 verst

Verst

A verst or werst is an obsolete Russian unit of length. It is defined as being 500 sazhen long, which makes a verst equal to 1.0668 kilometres ....

 (~99 km)) was constructed during 1796-1801. In 1803 it was decided to modernize and extend the road. The extension from Kutlushnoye to Posolsky Monastery was started in 1867. The latter stretch is associated with the uprising of Polish political exiles in Siberia

Uprising of Polish political exiles in Siberia

Siberian Uprising or Baikal Insurrection was a short-lived uprising of about 700 Polish political prisoners and exiles in Siberia, Russian Empire, that started on 24 June 1866 and lasted for a few days, till their defeat on 28 June....

of 1866.