Neusiedler Lake(noi`zēdlər), Ger. Neusiedlersee, Hung. Fertő tó, c.130 sq mi (340 sq km), on the Austria-Hungary border SE of Vienna. The lake's area and depth (average 5 ft/1.5 m) vary considerably with the seasons. The heavy growth of lake reeds supplies the Austrian cellulose industry. Carp fisheries are in the lake. Its lonely and desolate salt marshes attract a variety of wild life and have been protected since 1935. The Neusiedler region has noted resorts. There are remains of prehistoric lake dwellers in the vicinity.
a subsaline lake in Austria and Hungary, where it is called Fertő. Located in the western part of the Central Danubian Plain at an elevation of 115 m, it measures approximately 30 km from north to south and is 9 km across at its widest; its area is 323 sq km, and it is up to 2m deep. The shores are flat and extremely marshy. In the summer, during the wet season, the lake’s size increases. In the winter the lake sometimes freezes down to the bottom. In Hungary it is linked by canals with the Danube basin. Approximately 80 percent of the lake has dense growths of reeds, which provide nesting sites for waterfowl. There is a bird sanctuary of the same name in Austria.