The Saimaa Canal was built from 1845 to 1856 and opened for traffic in 1856. The canal was built between the cities of Lappeenranta and Viipuri (now Vyborg, Russia), both of them then in the autonomous Grand Duchy of Finland in the Russian Empire.
In the Moscow Peace Treaty of 1940, the Karelian Isthmus and the city of Vyborg were ceded to the Soviet Union, thus effectively splitting the canal in half and ending all traffic.
Following a treaty agreement in 1963, Russia leased the Russian section of the canal area to Finland for fifty years. Negotiations in 2008 agreed upon an extension of 50 years in 2013. A new deeper canal was constructed by the Finns and opened for traffic in 1968. The length of the canal itself is 43 km.
There is a height difference of 76 m between the levels of the Gulf of Finland and Lake Saimaa. There are 8 locks in the canal to level this difference.