The article examines the history of the temporary branch of the State Bank of the Russian Empire in Verkhneudinsk on the basis of archival documents found in the State Archive of the Republic of Buryatia and the State Archive of the Irkutsk Region, published sources and literature. The reasons for setting up a bank office on the territory of Western Transbaikal are identified, primarily due to the need to provide credit and financial services during the «most outstanding» Verkhneudinskaya Winter Fair with a turnover of more than two million rubles. The role of the director of the Irkutsk branch of the State Bank A. M. Mikhailovsky in the foundation and subsequent activities of the banking department is determined. The work of bank employees in providing typical banking services to the population of the region (lending, accounting for bills of exchange, making money transfers, accepting deposits) is analyzed, and the dynamics of credit and financial transactions is revealed. The influence exerted by the activities of the temporary branch on the economic development of Western Transbaikal and, in particular, on the formation of its banking system is established. The reasons for the short history of the branch and its closure are revealed, the main of which was the decline of the fair trade caused by the construction of the railway line.