The Kärnäkoski Fortress was built under the leadership of Russian General Alexandr Suvorov in 1791, as part of the defence system protecting St. Petersburg. The fortress that secured the border against Sweden served as a naval base on Lake Saimaa. The fortress became obsolete and was abandoned when Finland was joined to Russia in 1809.
The Empress orders the border to be secured
The Fortress and the Mountain Fort are erected
Activities are terminated at Kärnäkoski Fortress
The Empress Orders the Border to be Secured
In 1743, the Treaty of Åbo ended the Russo-Swedish war, known as the Hats' War and Southeastern Finland became part of Russia. Towards the end of the 1700s, the Swedes tried to reconquer their lost territory but failed in the Russo-Swedish War of 1788–90, known as Gustav III's War. Fierce battles took place, even in Kärnäkoski.
As result of this war, the Russians realised that Sweden posed a threat and rearmament of the border began by order of Empress Catherine the Great. In 1791, she dispatched General Alexandr Suvorov to build a chain of fortresses to secure the northwestern border of her empire. Suvorov did as he was told and the outer chain of fortresses that protected St. Petersburg was rapidly built in the early 1790s, under his leadership. The chain comprised the forts and fortresses of Kyminlinna, Liikkala, Utti, Järvitaipale and Kärnäkoski.
The Fortress and Mountain Fort Are Erected
Suvorov chose the western shore of the rapids as the site of the Kärnäkoski Fortress, as it enabled an easy watch over the road from Savitaipale to Mikkeli and the waterway to Lake Saimaa. The Fortress provided protection for the Russian fleet on Lake Saimaa.
The bastion fortress built in Kärnäkoski was 220 metres long and 150 metres wide. Curtain walls were constructed around the Fortress and wooden buildings inside the walls. The Fortress area also comprised a redoubt called Mountain Fort, a small stronghold supporting the main fortress, the Ratasalo battery and the Partakoski redoubt a couple of kilometres northwest of Kärnäkoski.
Russian troops, some 500–1,000 men on a daily basis, and local peasants worked on the building site. Many of them perished due to illnesses and heavy work. The Fortress was completed over a period of just over a year and in September 1792 Suvorov was able to boast that it was as "pretty as a flower". Some 400 military men were stationed in the Fortress. The main armament comprised two howitzers, field artillery guns, and initially 14 but later 24 guns.
In 1795, Engineer General Paul van Suchtelen criticised Suvorov's fortresses and proposed their modernisation. The plan was never implemented. New proposals for Kärnäkoski were made again in the early 1800s, but were never fulfilled. Emperor Alexander I visited Kärnäkoski in 1803, giving van Suchtelen the opportunity to present his criticism on-site. This resulted in new construction being initiated in other fortresses, such as Kyminlinna, but not in Kärnäkoski before the war broke out in 1808.
Activities Are Terminated at the Kärnäkoski Fortress
Russian troops advanced rapidly during the Finnish War and the Kärnäkoski Fortress was never the scene of military operations. Kärnäkoski lost its position as a border fortress in the Treaty of Hamina, concluded in 1809, but it was not until 1835 that the activities of inland fortresses were terminated by order of Emperor Nicholas I. The Kärnäkoski Fortress was disarmed and all usable materials, including the buildings, were auctioned.
Later, during the 1918 war, several battles between the opposing sides, the Whites and Reds, took place in the vicinity of Kärnäkoski.
The structures of the Kärnäkoski Fortress, particularly the collapsed walls, have been repaired on three occasions since the 1960s. Today, the site is managed by Metsähallitus Parks & Wildlife Finland.