République socialiste soviétique carélo-finnoise
On November 30, 1939, the Soviet Union waged the Winter War against neighbouring Finland and with the Moscow Peace Treaty in 1940 gained some territories, including the Karelian Isthmus. Their Karelian population was hastily evacuated to inner Finland and later replaced with people from other parts of the Soviet Union. A small part of the territory (the municipalities of Kanneljärvi, Koivisto and Rautu) was incorporated into Leningrad Oblast, the rest being included within the Karelo-Finnish Soviet Socialist Republic.