The article presents the results of a comprehensive archaeological and geophysical study of three lines of defensive structures of the Idnakar settlement of the IX-XIII centuries. The features of the shape, structure and construction of the embankments of each of them are revealed. The gradual expansion of the site with the construction of a new line of fortifications, their repeated strengthening indicate the intensive development of productive forces and demographic growth of the population, the strengthening of the internal potential of society and the development of fortified settlements of the Kama region along with the Bulgarian and Old Russian ones in the general course of urban development processes in Eastern Europe. Keywords: Kama region, Middle Ages, Idnakar settlement, system of fortifications, form and structure of defensive structures, interdisciplinary research, electrometry method, town-forming processes. Introduction In the historical and cultural reconstructions of the medieval Kama region in recent decades, an increasingly significant place is occupied by materials of fortified settlements, which indicate that at the turn of the first-second millennium AD, the largest of them developed in the general course of city formation processes [Ivanova, 1998; Drevnaya Afkula..., 2008]. One of the essential indicators of the social status of a settlement is defensive structures, which were of fundamental importance in the life and activity of the emerging ethnopolitical community. However, the study of ramparts and ditches, which requires significant labor costs, for a long time remained beyond the attention of researchers. In the Finno-Ugric settlements of the Kama region, almost no special studies were conducted, with the exception of the Verkh-Sayinsky settlement of the V/VT-X centuries, where the defense line was studied for 200 m, but the results were reflected only in a small publication (Goldina and Pastushenko, 2003). On the Vazhnangersky (Malo-Sund ... Read more