Vyborgsky District, Leningrad Oblast in the context of "Kymenlaakso"

The Karelian Isthmus (Russian: Карельский перешеек, romanized: Karelsky peresheyek; Finnish: Karjalankannas; Swedish: Karelska näset) is the approximately 45–110-kilometre-wide (30–70 mi) stretch of land situated between the Gulf of Finland and Lake Ladoga in northwestern Russia, to the north of the River Neva. Its northwestern boundary is a line from the Bay of Vyborg to the westernmost point of Lake Ladoga, Pekonlahti. If the Karelian Isthmus is defined as the entire territory of present-day Saint Petersburg and Leningrad Oblast to the north of the Neva and also a tiny part of the Republic of Karelia, the area of the isthmus is about 15,000 km (5,800 sq mi).

The smaller part of the isthmus to the southeast of the old Russia-Finland border is considered historically as Northern Ingria, rather than part of the Karelian Isthmus itself. The rest of the isthmus was historically a part of Finnish Karelia. This was conquered by the Russian Empire during the Great Northern War in 1712 and included within the autonomous Grand Duchy of Finland (1809–1917) of the Russian Empire. When Finland became independent in 1917, the isthmus (except for the territory roughly corresponding to present-day Vsevolozhsky District and some districts of Saint Petersburg) remained Finnish. Finnish Karelia was partly ceded to the Soviet Union by Finland following the Winter War (1939–1940) and Continuation War (1941–1944). In 1940–1941, during the Interim Peace, most of the ceded territories in the isthmus were included within the Karelo-Finnish SSR. However, since World War II the entire isthmus has been divided between the city of Saint Petersburg (mostly Kurortny District), as well as Priozersky District, Vsevolozhsky District and Vyborgsky District of Leningrad Oblast.

Vyborg (/ˈviːbɔːrɡ, ˈviːbərk/; Russian: Выборг, IPA: [ˈvɨbərk]; Finnish: Viipuri, IPA: [ˈʋiːpuri]; Swedish: Viborg, IPA: [ˈvǐːbɔrj] ) is a town and the administrative center of Vyborgsky District in Leningrad Oblast, Russia. It lies on the Karelian Isthmus near the head of Vyborg Bay, 130 km (81 miles) northwest of St. Petersburg, 245 km (152 miles) east of the Finnish capital Helsinki, and 38 km (24 miles) south of Russia's border with Finland, where the Saimaa Canal enters the Gulf of Finland. The most recent census population of Vyborg is 72,530 (2021 census).

Vyborg was founded as a medieval fortress in Finland under Swedish rule during the Third Swedish Crusade. After numerous wars between the Russians and Swedes, the Treaty of Nöteborg in 1323 defined the border of eastern Finland, and would separate the two cultures. Vyborg remained under Swedish rule until it was captured by the Russians during the Great Northern War. Under Russian rule, Vyborg was the seat of Vyborg Governorate until it was incorporated into the newly established Grand Duchy of Finland, an autonomous part of the Russian Empire. Finland declared its independence from Russia in 1917, after which Vyborg became its second-most significant city after Helsinki, and represented internationally as its most multicultural city. During World War II, Vyborg's population was evacuated and the town was ceded to the Soviet Union. In 2010, Vyborg was conferred the status of "City of Military Glory" by Russian president Dmitry Medvedev.

Vsevolozhsky District (Russian: Все́воложский райо́н) is an administrative and municipal district (raion), one of the seventeen in Leningrad Oblast, Russia. It is located in the central northwestern part of the oblast on the Karelian Isthmus and borders with Priozersky District in the north, Kirovsky District in the south, Vyborgsky District in the northwest, Nevsky, Krasnogvardeysky, Kalininsky, Vyborgsky, and Kurortny Districts of the federal city of St. Petersburg in the west, and is washed by Lake Ladoga in the east. The area of the district is 3,036.4 square kilometers (1,172.4 sq mi). Its administrative center is the town of Vsevolozhsk. Population (excluding the administrative center): 153,045 (2010 census); 131,233 (2002 Census); 135,318 (1989 Soviet census).

Priozersky District (Russian: Приозерский район) is an administrative and municipal district (raion), one of the seventeen in Leningrad Oblast, Russia. It is located in the northwest of the oblast and borders with Lakhdenpokhsky District of the Republic of Karelia in the north, Vsevolozhsky District in the south, and Vyborgsky District in the west. In the east, the district is bounded by Lake Ladoga. The area of the district is 3,597.5 square kilometers (1,389.0 sq mi). Its administrative center is the town of Priozersk. Population (excluding the administrative center): 43,260 (2010 census); 42,859 (2002 Census); 40,231 (1989 Soviet census).

Svetogorsk (Russian: Светогорск, Finnish: Enso) is an industrial town in Vyborgsky District of Leningrad Oblast, Russia, located on the Karelian Isthmus, on the Vuoksi River. It is located one kilometre (0.62 mi) from the border with Finland, five kilometres (3.1 mi) from the Finnish town of Imatra, and 207 kilometers (129 mi) from St. Petersburg. Population: 15,981 (2010 census); 15,698 (2002 census); 15,594 (1989 Soviet census).

Primorsk (Russian: Примо́рск; Finnish: Koivisto; Swedish: Björkö) is a coastal town in Vyborgsky District of Leningrad Oblast, Russia and is the second largest Russian port on the Baltic, after St. Petersburg. It is located on the Karelian Isthmus, 137 kilometers (85 mi) west of St. Petersburg, at the northern coast of the Gulf of Finland, near Beryozovye Islands (Finnish: Koivusaari (Koivistonsaari), Tiurinsaari ja Piisaari; Swedish: Björkö) which are protected as a sea bird sanctuary. Population: 6,119 (2010 census); 5,332 (2002 census); 6,637 (1989 Soviet census).