Zelenogorsk (Russian: Зеленого́рск; before 1948 Terijoki, a name still used in Finnish and Swedish), is a municipal town in the Kurortny District of the federal city of Saint Petersburg, Russia. The town is a suburb of Saint Petersburg. It’s located in part of the Karelian Isthmus on the shore of the Gulf of Finland, and has a station on the St. Petersburg-Vyborg railroad. It is located about 50 kilometers (31 mi) northwest of central Saint Petersburg.
Former Finnish officer club, later office building of the Finnish Democratic Republic
Following the Finnish War and until 1917, Terijoki was part of the Grand-Duchy of Finland, ruled by the Grand Dukes of Finland, who were the Tsars of Russia, (1812–1917).
Even though all of Finland was part of the Russian Empire, a customs border was located at Terijoki. A valid Passport was needed for crossing the border between Russia and the Grand Duchy of Finland.
Vladimir Lenin managed to travel over the border in secrecy to Finland in 1907. Later on 3 April 1917, he returned through the Terijoki border control disguised as a heater of a Finnish Railways — Finlyandsky Rail Terminal locomotive.
With completion of the Riihimäki-St. Petersburg railroad in 1870, Terijoki become a popular summer resort, and was frequented by St. Petersburg’s upper class until closure of the border during the Russian Revolution (1917).
When the Republic of Finland gained independence on 6 December 1917, Terijoki became a part of it, and remained so until it was occupied by the Soviet Union during the Winter War (1939-1940). It was regained by Finland in 1941 during the Continuation War (1941-1944), but then was then occupied again by the Red Army during the later stages of the same war and anexed to the Soviet Union in 1944.
During the Winter War Terijoki become known as the seat of Otto Ville Kuusinen’s Finnish Democratic Republic.
After the Second World War, its original Finnish population was displaced by people who moved from Russia. Around the start of the 21st century, the town’s population was estimated to have been a few thousand, rising to above 50,000 in summer.