Finland's defeat in the 1941–44 Continuation War against the Soviet Union led to the 1944 Moscow Armistice, under which Finland ceded Karelia, Petsamo, and other territories, later confirmed by the 1947 Paris Peace Treaty. Rather than live under Soviet rule, essentially the entire Finnish-speaking population of the ceded areas—about 410,000–430,000 people, over a tenth of Finland's population—evacuated to what remained of Finland, in an outcome Finland had also experienced on a smaller scale after the 1939–40 Winter War. Finland absorbed and resettled the evacuees under a dedicated land-redistribution program, avoiding the refugee camps seen elsewhere in postwar Europe. Vyborg, Finland's second-largest prewar city, and its surrounding region became part of the Soviet Union (later Russia).
Under the 1944 Moscow Armistice (confirmed by the 1947 Paris Peace Treaty), Finland ceded Karelia and other border areas to the Soviet Union; virtually the entire Finnish population evacuated westward rather than remain under Soviet rule.
The ceded territory, about 11 per cent of Finland's area, held roughly 410,000-430,000 people, some 11-12 per cent of a national population of 3.7 million. Virtually the entire population was evacuated to the rest of Finland, first in 1940, then partly returning during the Continuation War, and finally in 1944; the Land Acquisition Act of 1945 resettled them across the country.
The 1944–45 cession and evacuation is not documented to have caused significant loss of life: the movement of roughly 400,000 Karelians into Finland proper was organised by the Finnish state under armistice terms and carried out largely without violence, and Finland's wartime deaths belong to the Winter and Continuation Wars rather than to the transfer itself. No source provides a death range for the evacuation.
Russia, Finland