This article offers a historiographical analysis of the socio-economic consequences of Estonia’s incorporation into the Soviet Union in 1940 and the policy of forced resettlement associated with the ensuing transformations. The study aims to clarify the political and economic measures introduced by the Soviet authorities in Estonia and to identify the mechanisms, scale, and consequences of migration and deportation from the Baltic region to the Kazakh SSR. The source base includes records from the Archive of the President of the Republic of Kazakhstan, state and departmental archives of the Russian Federation, NKVD reports, Communist Party statistics, published document collections, and deportees’ memoirs. Historical-comparative, historiographical, systemic, and source-critical methods were combined with the comparison of quantitative data. The study establishes that the number of Estonians recorded in Kazakhstan’s party organizations increased between 1940 and 1943. It also identifies Lutheran clergy among the deported population and examines the transfer of religious property and infrastructure to state control. The analysis further considers the impact of Soviet economic centralization on foreign trade, private property, and overseas investment in Estonia. A comparison of Soviet, post-Soviet, and Western scholarship reveals divergent legal assessments of the 1940 events, estimates of deportation, and interpretations of their social consequences. The article concludes that adaptation in Kazakhstan was accompanied by weakened linguistic and cultural continuity and that further research requires systematic cross-checking of archival statistics, administrative records, and personal testimony.