<abstract> <p>One of Russia's strategic objectives is to identify and create conditions to ensure accelerated development of promising centers of economic growth in the country's regions. In practice, most of these centers are cities of different levels of hierarchy, which create or have the potential to create urban agglomerations on their basis. At the same time, at present, most attention is paid to the study of the largest and large urban agglomerations not only in domestic, but also in the world science; while the real prerequisites and processes of second-tier agglomerations development are studied rather poorly. In this regard, the purpose of this paper was to analyze and identify the specifics of agglomeration processes in several Russian second-tier agglomerations. To achieve this purpose, we used a wide range of both general scientific (analysis, synthesis, structural-functional, etc.) and applied economic and mathematical methods (index method, correlation analysis, calculation of the Theil index). The main conclusions of the research was that the key trend of these agglomerations' development was the increasing concentration of an already high share of regional production, investment, and population against the background of growing intra-regional heterogeneity. At the same time, agglomeration processes themselves spread only to the territory closest to the core, which is manifested in the convergence of growth rates of these territories in terms of key socio-economic indicators. All this proves the underdevelopment of the satellite zone of second-tier agglomerations and the hypertrophied development of the core: weak interconnectedness of their reproductive processes, which may be a threat to the development of such agglomerations as integrated socio-economic systems and growth centers of regional and macro-regional significance in the future. The authors showed that a number of northern/arctic agglomerations (Surgut, Arkhangelsk) have a significant development potential due to not only the formed economic base of their satellite zone, but also socio-economic connectivity along the line "core-satellite zone". The scientific novelty of the presented research lies in the development of approaches, substantiation of methodological tools for assessing agglomeration processes, and identification of the specifics of these processes in Russian second-tier agglomerations on the basis of its testing.</p> </abstract>