Which Austria-Hungary lake is the largest endorheic lake in Central Europe?

Lake Neusiedl is the largest endorheic lake in Central Europe, shared by Austria and Hungary.

Known as Neusiedler See in German and Fertő tó in Hungarian, the shallow saline lake covers about 315 square kilometres. Roughly 240 square kilometres lie in Austria and 75 square kilometres in Hungary. It is about 36 kilometres long but generally no more than 1.8 metres deep.

“Endorheic” means that water does not normally drain to the sea through a natural river system. Lake Neusiedl loses most of its water through evaporation; the Einserkanal is an artificial outflow. Its water levels have fluctuated dramatically, and the lake has completely or almost completely dried out several times, including in 1740–1742, 1811–1813 and 1866.

The lake is not Central Europe’s largest lake overall—Lake Balaton is larger—but the endorheic qualifier makes Neusiedl the canonical answer. Its reed beds and surrounding wetlands also support major migratory-bird habitats.