Lake Ladoga is a freshwater lake located in the Republic of Karelia and Leningrad Oblast in northwestern Russia just outside the outskirts of Saint Petersburg. It is the largest lake in Europe, and the 15th largest freshwater lake by area in the world.

The lake has an average surface area of 17,891 km2 (excluding the islands). Its north-to-south length is 219 km and its average width is 83 km; the average depth is 51 m, although it reaches a maximum of 230 m in the north-western part. Basin area: 276,000 km2, volume: 837 km3. There are around 660 islands, with a total area of about 435 km2. Ladoga is, on average, 5 m above sea level. Most of the islands, including the famous Valaam archipelago, Kilpola, and Konevets, are situated in the northwest of the lake.

Separated from the Baltic Sea by the Karelian Isthmus, it drains into the Gulf of Finland via the Neva River.

More Info: en.wikipedia.org