塞马湖是芬兰最大的湖泊，也是欧洲第四大湖泊，位于芬兰的南部。塞马湖也是塞马环斑海豹的栖息地，牠同时也是世界上三种淡水海豹之一。

Saimaa is a lake in southeastern Finland. At approximately 4,400 square kilometres (1,700 sq mi), it is the largest lake in Finland, and the fourth largest natural freshwater lake in Europe. It was formed by glacial melting at the end of the Ice Age. Major towns on the lakeshore include Lappeenranta, Imatra, Savonlinna, Mikkeli, Varkaus, and Joensuu. The Vuoksi River flows from Saimaa to Lake Ladoga. Most of the lake is spotted with islands, and narrow canals divide the lake in many parts, each having their own names (major basins include Suur-Saimaa, Orivesi, Puruvesi, Haukivesi, Yövesi, Pihlajavesi, and Pyhäselkä).