1 / 4 Saimaa: its origins, flora and fauna Saimaa is a labyrinthine watercourse whose waters flow slowly from north to south and finally through its outflow channel, the Vuoksi, southeast over the Russian border into Ladoga, Europe's largest lake. The Saimaa drainage region covers most of the southern part of eastern Finland, a region about the size of Belgium, extending almost to Lake Oulujärvi in the north and just over the Russian border in the east. In places, there is more shoreline here per unit of area than anywhere else in the world, the total length being nearly 15,000 km. The number of islands in the region, 14,000, also shows what a maze of detail the system is. Towards the end of the Ice Age, landscape features were created by meltwater gravel deposits. Venäjänsaari, Taipalsaari.