The settlement of the borderland after World War II was the biggest internal migration of people in the history of the Czech land. The process (including the forced migration) covered more than five million people. From the point of view of timing as well as organization the settlement was conducted simultaneously with the forced migration of the German population from Czechoslovakia, particularly from the Czech region, Moravia and the Czech Silesia. These were two sides of the same coin, two phases of the same process which were interrelated and conditioned each other. They were two integral elements of one phenomenon: reorganizing the ethnic structure of the Central and Eastern Europe after World War II and the extent of migration, particularly in the Czech area was unprecedented. Hence it is surprising that the research on this problem in the Czech historiography is delayed, compared for instance to the Polish historiography. The phenomenon triggered far-reaching changes which exerted a significant influence on the lives and thinking of millions of people over the following dozens of years.