The village of Möhkö grew around one of Finland's largest ironworks, founded in 1838 to refine iron from limonite. Wars took a heavy toll on Möhkö. On the fateful day of 7 December  1939, a Soviet division entered the village. The occupation lasted until the hostilities ended on 13 March  1940. 

Most civilians had been evacuated from Möhkö and other easternmost villages and settlements of Ilomantsi a few days before the outbreak of the Winter War on 30 November  1939. The Red Army's 155th Division of 18,000 men crossed the old border into Finland along three axes in Ilomantsi sector. The division consisted of three regiments of 6,000 men each. On the northern flank, one regiment pushed toward Kallioniemi on the road that led to Hattuvaara, while the other two advanced in the direction of Möhkö with Ilomantsi parish village as their objective. 

The defending force consisted of 900 combat-ready men, which meant that the attacker had a twenty-fold superiority in numbers. After one week of fighting delaying actions, the retreating Finnish forces reached Möhkö on Finland’s Independence Day, 6 December. They were followed by the leading enemy elements. The next day, the defenders blew up the Koitajoki River bridge and retreated to Oinassalmi. 

Two Red Army regiments comprising a total of 12,000 men and 1,470 horses immediately set about building shelters for encampment. Some of these were proper timber-shored structures, others mere shacks roofed with narrow strips of wood and tree branches. There was no other way to provide billeting facilities because the Finnish forces had burned down nearly all buildings on the northeastern side of the river before the Russian troops’ arrival. The front stabilised at Möhkö until the end of the Winter War. Dugouts and other fortifications remain visible even today. 

A red granite memorial to the Finnnish 21st Brigade stands next to the Koitajoki bridge in the village. The brigade saw action during the Continuation War at Öykkösenvaara in 1944. 

Möhkö Ironworks Museum has three rooms dedicated to military history. The museum is open from June to August.