Vast Open Water and a Labyrinth of Islands
Lake Kermajärvi is 84 sq. km in size and it is the main lake on the Heinävesi Water Route. Kermajärvi is 13 km long and there are 25 sq. km of land and 18 sq. km of water within it. It is important as an undisturbed inland water area in Southern Finland, where shoreline, island and open water natural features as well as forests are protected.
To the west the Kermajärvi landscape is dominated by vast open water, Kytöselkä and Kermanselkä. The Osprey (Pandion haliaetus) can often be seen circling above the waters. In the east part of the area the open waters end and a dense labyrinth of islands begins. The sounds and currents of this area separate large islands and rocky islets from one another. The largest islands are Hentulansaari, Kurjenvarvas and Puumalansaari. These islands are large enough to accommodate the area's abundant moose population.
The sight that will catch visitors' attention in the southeast part of the area is the 1-km-long Cape Hyövynniemi and in the northwest Cape Kohmanniemi, which is almost as long. Both capes are long and narrow and run in a northwest southeast direction which is characteristic of Kermajärvi.
The shores in Kermajärvi are barren and rocky and vegetation is scarce. There are small rocky islets with no vegetation, which are nesting spots for the Lesser Black-backed Gull (Larus fuscus) and the Common Tern (Sterna hirundo). These birds are very sensitive and there nesting is disturbed very easily.
Big changes in altitude are common on the islands in Lake Kermajärvi. There are many bare cliffs and precipices. Beautiful views of lakeland scenery open from the top of the areas many hills. The highest spot in the area is the top of Pyylinvuori Hill. It is located on Cape Kohmanniemi and rises to a height of 30 m. The area's high hills and open cliff top pine forests offer the Northern Eagle Owl (Bubo bubo) and ideal terrain for hunting hares, among other things.
The diverse forest landscape is for the most part made up of dry evergreen forest, but in some hollows there are also lush herb-rich forests.