With its six square kilometers of water area the Wallersee is the largest lake of the Salzburg Lake District.
The name of the lake stems not from the existing in the lake Wallern (= catfish) but from the Middle High German Walchen what strangers meant. So were all the Latin peoples (also sometimes romanized population of the Alps) south of Bavaria for the locals Welsche or just Walche.
Nature reserve Wengermoor
Large parts of the Köstendorfer share of the lake attributable to the nature reserve Wenger Moor. Also the reeds along the lake are protected. Gray heron, plover, curlews, ducks, pheasants, grebes, coots, jays, swans and black-headed gulls are among the inhabitants of the reed belt and the lake, which is also rich in fish species: catfish, bream, pike, carp, eel, trout and tench romp in the waters.
- At Wallersee there is no commercial shipping. However, there are smaller yachts up to 30 feet as well as boat rentals and organized boat trips.
- The Wallersee served for many well-known writers as a source of inspiration. Among them: Sylvester Wagner, John Freumbichler Zuckmayer, etc.