The migration balance of urban municipal areas (hereinafter, okrugs–Russ.) and municipal districts in Russia in 2012–2014 is analyzed from the standpoint of its impact on the concentration and deconcentration of the population. The paper reviews the distribution of urban okrugs and municipal districts by population density and the current ratio of sparsely and densely populated areas across the country. Calculations show that the conditions in Russia today contribute to concentration of the population and, hence, the polarization of space between densely populated major cities and deserted poorly developed areas. Unlike in many European countries and the United States, where concentration and deconcentration processes have been alternating for decades, concentration of the population is an ongoing process in Russia. Two directions of migration are analyzed: (1) from the intraregional periphery to regional centers: the farther from the center, the more intense the outflow; (2) from low-populated municipalities to densely populated territorial units, primarily, large cities. The contributions of individual migration flows (intraregional, interregional, and international) to the concentration and deconcentration of the population are evaluated.