Lake Onega is the second-largest lake in Europe by surface area, after Lake Ladoga.
The lake lies in northwestern Russia, mainly within the Republic of Karelia, with parts in Leningrad Oblast and Vologda Oblast. It covers about 9,700 square kilometres, although measurements vary slightly depending on whether nearby islands and connected water areas are included. Its waters drain northward through the Svir River into Lake Ladoga and then toward the Gulf of Finland.
Lake Onega is notable for its many islands and its long, branching shape. Kizhi Island, located in the lake, is famous for the Kizhi Pogost, a historic ensemble of wooden churches and a UNESCO World Heritage Site. The lake also supports fishing, shipping and tourism, and it is connected to major waterways through canals.
A common mix-up is confusing Lake Onega with Lake Ladoga. Ladoga is larger and is Europe’s largest lake by surface area; Onega is second. Lake Vänern is Europe’s third-largest by surface area and lies in Sweden.