After the Winter War, Finland had to cede the Karelian Isthmus and Ladoga Karelia to the USSR. As the local Karelian population was unwilling to end up under Soviet rule, over 400,000 people were evacuated across Finland's new border from the territories that were to be ceded. After the Continuation War (1941–1944), in which Finland temporarily held most of Eastern Karelia, several thousands of Karelians chose to migrate west as Finnish forces retreated. The Karelians who migrated to Finland in the 20th century were initially Karelian speakers, but due to minor lingual differences and in order to assimilate into the local communities soon adopted the Finnish language after the war. Some of the evacuees later immigrated, mainly to Sweden, Australia and North America.