The Königssee is a lake located in the extreme southeast Berchtesgadener Land district of the German state of Bavaria, near the border with Austria. Large parts are comprised by the Berchtesgaden National Park.
Lying within the Berchtesgaden Alps in the municipality of Schönau am Königsee, just south of Berchtesgaden and the Austrian City of Salzburg, the Königssee is Germany's third deepest lake. Located at a Jurassic rift it was formed by glaciers during the last ice age. It stretches about 7.7 km (5 mi) in the north-south direction and is about 1.7 km (1 mi) across at its widest point. Except at its outlet, the Königsseer Ache at the village of Königssee, the lake similar to a fjord is surrounded by steeply rising flanks of mountains up to 2700 m (8900 ft), including the fabled Watzmann massif in the west.
The literal translation appears to be "King's Lake", however while German: König does indeed mean "king", there had been no Bavarian kings since the days of Louis the German until Elector Maximilian I Joseph assumed the royal title in 1806. Therefore the name more probably stems from the first name Kuno of local nobles, who appear in several historical sources referring to the donation of the Berchtesgaden Provostry in the 12th century; the lake was formerly called Kunigsee.
In 1944 a subcamp of the Dachau concentration camp was located nearby where Heinrich Himmler had a residence built at Schönau for his mistress Hedwig Potthast.
The lake is noted for its clear water and is advertised as the cleanest lake in Germany. For this reason, only electric driven passenger ships, rowing and pedal boats have been permitted on the lake since 1909. Due to its picturesque setting, the lake and surrounding parklands are very popular with tourists and hikers. In addition, the lake's position surrounded by sheer rock walls creates an echo, which is known for its clarity. On boat tours, it has become traditional to stop and play a flugelhorn or trumpet to display the echo; formerly demonstrated by shooting a cannon, it could be heard reflected up to seven times.