The Siberian fortifications of the 17–18th centuries represent an important part of Russian wooden architecture, significant both for world and local histories of the development of wooden architecture. The identification of specific architectural and construction approaches used to erect fortresses during the epoch of the accession of Siberia to Russia, namely the East Siberia and the Amur Region, is es-sential for studying the main principles of establishing ostrogs (fortresses) and settlements. The study is aimed at clarifying the meaning of such architectural and construction terms of Russian wooden for-tification architecture as “gorodnya” and “nagorodnya”, which are encountered in historical sources of the 17th century compiled by Russian explorers and fortress builders. The following research methods were used: systemic approach, analogic method and complex approach with the application of architec-tural 3D markers representing the units of specific historico-architectural and town-building infor-mation, which were preserved in the data about the studied object. Textual, graphic and archaeological materials were used. The main results included the widening of "gorodnya" and "nagorodnya" architec-tural and construction terms of the 17–18th centuries, as well as the graphic reconstruction of Albazino Ostrog walls in accordance with new scientific data. Despite the fact that options for the reconstruction of such fortress walls have been proposed previously, the clarifications in this work are more objec-tive. The obtained results can be used for a more precise organisation of historical, architectural, town-building and archaeological works, as well as in restoration and reconstruction processes.