The article analyses migration from border countries (the so-called overlapping area) of two migration subsystems - Eurasian (centred in the Russian Federation) and European (the European Union) from 1991 to 2021 (before the recent events in Ukraine). A step-by-step analysis of the migration situation in the countries of the former USSR - Belarus, Latvia, Lithuania, Moldova, Ukraine and Estonia was conducted. The article examines bilateral and multilateral migration processes, analyses the main factors influencing their development and explores migration policy measures and their impact on the regulation of migration processes in the countries of the overlapping area. These countries, located between the two centres of major migration subsy...