Lake Saimaa is Finland’s largest lake and the fourth-largest natural lake in Europe by surface area.
Lake Saimaa is a highly fragmented lake system in southeastern Finland, covering about 4,400 square kilometres. It contains thousands of islands, narrow channels, and interconnected basins, so its shoreline is extraordinarily long compared with its area.
The lake is home to the endangered Saimaa ringed seal, a freshwater subspecies that became isolated from marine ringed seals after the land rose following the last Ice Age. Conservation work focuses on protecting breeding sites and reducing disturbance during the seal’s winter season.
The Saimaa Canal connects the lake system with the Gulf of Finland. Lake Saimaa is not a single simple open basin like many large lakes; its intricate geography is central to both its name and its ecological importance.