[8] It is known that during the 16th and 17th centuries a settlement existed here known as Shuyezersky pogost (a Russian form of the local Karelian name, meaning "swampy lake").

An outcome of the Winter War was that most of West Karelia was occupied by the Soviet Union in 1940, when Suoyarvi was granted town status.

[citation needed] In August 1941, the territory was re-occupied by Finnish troops, but as part of the wider post-war settlement, it reverted to the Soviets in 1944; it was the second largest territory by area (after Petsamo) ceded by Finland to the Soviet Union following the Continuation War.

[9] Suoyarvi had its own dialects of the Karelian language before the area was ceded to the Soviet Union and its inhabitants were relocated to other parts of Finland.

Most of the Karelian people in the former municipality spoke a variety of South Karelian (suvikarjala), while the villages in the Hyrsylä (Khyursyulya) salient, which also included Ignoila (Ignoyla) and Hautavaara (Khautavaara), spoke a Livvi dialect instead.