The paper presents the results of a complex historical and dendrochronological study of folk architecture of peasant-migrants of the first quarter of the 20th century who lived in the territory of the Middle Angara River region (Bratsk district of Irkutsk Oblast). Based on the dendrochronological studies, visual inspection of buildings and interviews with local residents, initial features and dynamics of adaptation changes in the building culture of the peasant-migrants were reconstructed. It has been established that the migrants tried to preserve as much as pos-sible of the building technologies from their homeland, changing only those elements that impeded the adaptation in the new environmental and climatic conditions. At the same time, a significant proportion of the peasant-migrants tried to reproduce at the new place those examples of folk architecture that in their homeland were cha-racteristic of most prosperous peasants. It has been concluded that in the Bratsk district, the building culture of the migrants underwent a higher degree of transformations than in other areas of the Angara basin region. Those mi-grants who settled in the vicinity of Russian old-settlers experienced heavy influences from their folk architecture.