Transbaikal Oblast
The Transbaikal Oblast () was a province (oblast) of the Russian Empire, in what is now Buryatia and Zabaykalsky Krai. The oblast was created out of the territory of the Irkutsk Governorate in 1851, and was dissolved in 1917, it was briefly re-established from 1920 to 1922 before it was succeeded by the Transbaikal Governorate. Geography 
The Transbaikal oblast was located in Eastern Siberia, to the south and east of Lake Baikal. Internally it bordered the Irkutsk Governorate to the west and north— separated mostly by Lake Baikal— to the northeast by Yakutsk Oblast and to the east by the Amur Oblast. To the south it bordered the Qing dynasty and later Mongolia and the Republic of China. History 
The Russians first explored Transbaikalia in 1639, when Maksim Perfilyev sailed up the Vitim River up to the mouth of the Tsipa. In 1647, Ivan Pokhabov crossed Lake Baikal and, being friends with the Mongols, explored to Urga. A year later, a proper settlement of the region was founded when the Barguzin fortress was founded, collecting tribute (yasak) from the Tungusic peoples in the region. In 1654 the Nerchinsk fortress was founded, 4 years later it was moved to the mouth of the Nercha and the city of Nerchinsk was founded. In 1665, Selenginsk was founded, followed by Verkhneudinsk the next year. By the end of the 17th century, there were 3 cities and 9 fortresses (ostrogs) in the region. Transbaikalia from the start of its settlement served often as a place of exile. According to the Supreme Decree presented to the Governing Senate on 11 July 1851, the Transbaikal Oblast, consisting of two districts — Verkhneudinsk and Nerchinsky was separated from the Irkutsk Governorate and became its own region (oblast), while Chita was elevated to a city of regional significance. The Frontier Cossacks, consisting of the Transbaikal City cossack Regiment, the village Cossacks, the Tungus and Buryat regiments as well as the population who lived in the border strip made up the Baikal Cossacks of the Transbaikal Cossack Host, which was obliged to field 600 cavalry regiments. In 1884, the region, previously subservient to the General Government of East Siberia, was re-assigned to the General Governorate of Amur, later it would be transferred again on March 17, 1906 to the General Governorate of Irkutsk. It was abolished in 1917 with the Russian Revolution but was re-established under the Far Eastern Republic in 1920, 2 years later it was abolished again and succeeded by the Transbaikal Governorate, which would later be abolished in 1926. Administrative Divisions 
The region was headed by a military governor, whose position was combined with the positions of the commander of the troops and the chief Ataman. The Cossack villages were distributed among three military departments, whose atamans supervised the regular serving of military service by the Cossacks. stanitsas were subordinated not to atamans, but to (civilian) county chiefs. The Chita district was the most complex, consisting of Cossack villages (stanitsas), peasant volosts, and nomad steppe dumas. Independent cities

List of military governors

Vice-governors and chairmen of the regional government (college)

Demographics 
There were 590,000 inhabitants in 1892, including 303,200 men. The predominance of men is explained by the annual influx of free and exiled migrants, thanks to this same migration, the population growth of the Transbaikal oblast was slightly higher than the population growth of the empire. The population was mostly located in 7 cities: Barguzin, Selenginsk, Troitskosavsk, Verkhneudinsk, Chita, Nerchinsk and Aksha, with another 750 settlements as well. Cossacks numbered 177,000, or 30.5% of the total population, while peasants numbered 166,000, 28.9% of the total population and foreigners numbered 170,000 (29%). The rest of the population was made up of townspeople, troops, convicts and exiled people, at 4% of the population. Curiously, almost the entire peasant population and more than 4/5 of all Cossacks were Old Believers. Outside of Christianity, Lama Buddhism was the most widespread, whose adherents were mostly Buryats and the Tungus, shamanism was also practiced. By 1860 there were 157 Buddhist and shamanic temples, by the modern day this number decreased by 2/3. The border was guarded by the cossacks, while the peasant population tended to live along the river valleys of rivers like Dzhida, Chikoya, Khilka, Onon and Argun. Ethnic composition and population in 1897 
The population according to the 1897 census was 672,037, consisting of 342,543 men and 329,494 women. Of these, Orthodox Christians numbered 443,009, Buddhists numbered 174,227, and Old Believers numbered 36,623. The urban population was 42,778. References

Oblasts of the Russian Empire
Transbaikal Oblast
Irkutsk Governorate
Former administrative divisions of countries