The forts of Kärnäkoski and Partakoski are situated in Savitaipale in South Karelia on the main road leading from Lappeenranta to Mikkeli in Savo. They are built on the isthmus between the lakes of Kuolimojärvi and Saimaa about 10 km north of the village of Savitaipale.

1791 Under the command of General Alexander Suvorov, Russia builds forts at Kärnäkoski and Partakoski as part of the new defence system for St. Petersburg. They are intended as a base for Russia's Saimaa fleet on the waterway between the fortress of Lappeenranta and Olavinlinna (Savonlinna). The fortress of Kärnäkoski was built in an irregular shape. It consists of irregular interconnected bastion and tenaille walls. The fort of Partakoski is also an irregular fortification that follows the contours of the landscape.

Post 1809 Russia disbands the forts of Kärnäkoski and Partakoski.

1980s restoration of the fort of Kärnäkoski begins.

The National Board of Antiquities and the Ministry of Labour have restored the fort of Kärnäkoski for tourist use. It is open to the public but there are no regular guided tours.