The Karelian Isthmus (Russian: Карельский перешеек) is the approximately 45–110 km wide stretch of land, situated between the Gulf of Finland and Lake Ladoga in northwestern Russia, to the north of the River Neva (between 61°21’N, 59°46’N and 27°42’E, 31°08’E). Its northwestern boundary is the relatively narrow area between the Bay of Vyborg and Lake Ladoga. If the Karelian Isthmus is defined as the entire territory of present-day Saint Petersburg and Leningrad Oblast to the north of the Neva, the isthmus' area covers about 15,000 km2.
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 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.
Russia i// or // (Russian: Россия, tr. Rossiya; IPA: [rɐˈsʲijə] ( listen)), also officially known as the Russian Federation (Russian: Российская Федерация, tr. Rossiyskaya Federatsiya; IPA: [rɐˈsʲijskəjə fʲɪdʲɪˈratsɨjə] ( listen)), is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects. From northwest to southeast, Russia shares land borders with Norway, Finland, Estonia, Latvia, Lithuania and Poland (both with Kaliningrad Oblast), Belarus, Ukraine, Georgia, Azerbaijan, Kazakhstan, China, Mongolia, and North Korea. It shares maritime borders with Japan by the Sea of Okhotsk, and the U.S. state of Alaska across the Bering Strait. At 17,075,400 square kilometres (6,592,800 sq mi), Russia is the largest country in the world, covering more than one-eighth of the Earth's inhabited land area. Russia is also the world's ninth most populous nation with 143 million people as of 2012. Extending across the whole of northern Asia, Russia spans nine time zones and incorporates a wide range of environments and landforms. Russia has the world's largest reserves of mineral and energy resources and is the largest producer of oil and natural gas globally. Russia has the world's largest forest reserves. Its lakes contain approximately one-quarter of the world's liquid fresh water, 20% in Lake Baikal alone.