The Finnish nickel deposits were found in the Petsamo area at Barents Sea, which until the Paris Peace Treaty was the northernmost part of Finland. In 1934 it was estimated that the deposits contained over five million tons of nickel. Mining operations started in 1935 by Canadian and French corporations.

The nickel was a lesser known reason for Allied and Third Reich interest in the area during World War II, as potentially of great importance for production of munitions, tanks and other war material. Both the planned Franco-British support of Finland in the Winter War, and the following German occupation of Denmark and Norway (Operation Weserübung) were to some degree motivated by the wish to deny the respective enemy nickel critical for wartime production. In early 1941, Nazi Germany had secured her control of the area with a military presence considered important by Finland for her security against the Soviet Union.

In September 1944, at the end of Finland's Continuation War, when the German power was broken, Finland had to give up this territory to the Soviet Union.