Wikipedia
Kermajärvi (literally Finn. kerma for cream, järvi for lake) is a medium-sized lake in the Vuoksi main catchment area. It is located in the region of Southern Savonia in Heinävesi. It is the country's 53rd largest lake with an area of and consists of a wide open lake with plenty of islands in both northwest and southeast parts of it and several long, narrow bays in both ends.
The lake gets its water from Varisvesi of Kallavesi by Karvio Rapids and flows through Kerma and Vihovuonne Rapids to Ruokovesi which flows through Pilppa Rapids to Haukivesi of Saimaa. Kermajärvi is the main lake of Heinävesi Route, one of the two routes which Lake Kallavesi flows through to Saimaa (the other being Leppävirta Route). All the four rapids can be evaded with canals built around the turn of the 19th and 20th centuries named after the adjacent rapids. Farthest extension of the lake from northwest to southeast is some . The northwest-southeast form shows the orientation of the moving Glacier in the latest Ice Age.
Heinävesi parish village is located on the southern shore of the lake.
A big part of the lake is protected in Natura 2000 conservation program (code FI0500011).