Lake Onega Lake Onega Lake Onega (also known as Onego, ; or ; or ; or ) is a lake in the north-west European part of Russia, located on the territory of Republic of Karelia, Leningrad Oblast and Vologda Oblast. It belongs to the basin of the Baltic Sea, Atlantic Ocean, and is the second largest lake in Europe after Lake Ladoga. The lake is fed by about 50 rivers and is drained by the Svir River. There are about 1,650 islands on the lake. They include Kizhi, which hosts a historical complex of 89 orthodox wooden churches and other wooden constructions
Lake Ladoga concentrated ice of the Fennoscandian Ice Sheet into an ice stream that fed glacier lobes further east. Deglaciation following the Weichselian glaciation took place in the Lake Ladoga basin between 12,500 and 11,500 radiocarbon years BP. Lake Ladoga was initially part of the Baltic Ice Lake (70–80 m. above present sea level), a historical freshwater stage of Baltic Sea. It is possible, though not certain, that Ladoga was isolated from it during regression of the subsequent Yoldia Sea brackish stage (10,200–9,500 BP). The isolation threshold should be at Heinjoki to the east of Vyborg, where the Baltic Sea and Ladoga