The first Russian Cossacks appear in Buryatia’s history in the middle of the 17th century.
They brought new forms of economy and life to the region and adapted them to local natural and climatic conditions. From XVII to XX centuries, Cossacks were the main military force; they served in Ostrogs (burgs) and along the border lines of Transbaikalia.
The increase of Cossacks number caused the growth of the agricultural population.
In the XVIII century, the number of Russian peasants in the Transbaikalia increased, they settled along the more advantageous places for agriculture and industry: along large rivers and their affluents. According to the 2002 census, Russians accounted for 68%, there is 665.4 thousand Russians in Buryatia nowadays.