This Element explains the historical conditions for the seemingly anomalous presence of people outside of 'their own' Soviet republic and the sometimes-fraught consequences for them and their post-Soviet host countries. The authors begin their inquiry with an analysis of the most massive displacements of the Stalin era - nationality-based deportations, concluding with examples of the life trajectories of deportees' children as they moved transnationally within the Soviet Union and in its successor states. The second section treats disparate parts of the country as magnets attracting Soviet citizens from far afield. Most were cities undergoing vast industrial expansion; others involved incentive programs to develop agriculture and rural-based industries. The final section is devoted to the history of immigration and emigration during the Soviet period as well as since 1991 when millions left one former Soviet republic for another or for lands farther afield.