This article is based on research of international ethnic-migrants’ residential concentrations in Russian cities. The research is based on the uncertainty as to whether such concentrations exist in Russia; there is scholarship which both supports and refutes this thesis. Stemming from the social-ecology approach of the Chicago School of Sociology, the authors concentrate on locations in three Russian cities where the residential concentration of migrants is the highest. These places are the town of Kotelniki in Moscow Region, Sortirovka in Yekaterinburg, and KrasTEC in Krasnoyarsk. Utilizing both field and theoretical methods, the authors describe how these places appeared and what processes occur there. Based on a comparative analysis, the authors hypothesize a pattern which lies behind these cases and distinguishes these cases from other-country cases. According to the hypothesis, migrants form residential concentrations around those large markets which started appearing on the peripheries of Russian cities after the collapse of the Soviet Union. In the following decades, the succession of the migrant population also settled there, and now a substantial share of these neighborhoods’ population are migrants, both those who work at the market and their relatives and friends who work in other parts of cities. Additionally, the migrant infrastructure evolved, and the neighborhoods started to be considered as ethnic and migrant.