Swedish iron ore was an important economic and military factor in the European theatre of World War II, as Sweden was the main contributor of iron ore to Nazi Germany. The average percentages by source of Nazi Germany’s iron ore procurement through 1933–43 by source were: Sweden: 43.0 Domestic production (Germany): 28.2 France: 12.9. Within the German military the Navy was most dependent on Swedish steel as an absolute necessity to the German war effort, according to their grand admiral. It has also been argued that the Swedish export helped prolong the war.
Both the Allies and the Axis were keen to gain control of the mining district in northernmost Sweden, surrounding the mining towns of Gällivare and Kiruna. The importance of this issue increased after other sources of iron were cut off from Germany by the Allied naval blockade during the Battle of the Atlantic. Both the planned Anglo-French support of Finland in the Winter War and the following German occupation of Denmark and Norway during Operation Weserübung were to a large extent motivated by the wish to deny their respective enemies iron critical for wartime production of steel.
