The Arendsee is a natural lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 in the Altmark

Altmark

The Altmark is a historic region in Germany, comprising the northern third of Saxony-Anhalt. As the initial territory of the Brandenburg margraves, it is sometimes referred to as the "Cradle of Prussia", as by Otto von Bismarck, a native from Schönhausen near Stendal.- Geography :The Altmark is...

 region, northern Saxony-Anhalt

Saxony-Anhalt

Saxony-Anhalt is a landlocked state of Germany. Its capital is Magdeburg and it is surrounded by the German states of Lower Saxony, Brandenburg, Saxony, and Thuringia.Saxony-Anhalt covers an area of...

, Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

. It is 23.3 m above sea level, and its area is 5.14 km², its depth nearly 50 m. It is the largest and deepest natural lake in Saxony-Anhalt.

The like lies on top of a salt dome

Salt dome

A salt dome is a type of structural dome formed when a thick bed of evaporite minerals found at depth intrudes vertically into surrounding rock strata, forming a diapir....

 and developed by repeated caving-in events that continued into historical time; at the end of the 19th century it was believed to have been created by an earthquake in 815. Hydrologically, the lake is more or less isolated with only a small artificial outflow connecting with the Elbe

Elbe

The Elbe is one of the major rivers of Central Europe. It rises in the Krkonoše Mountains of the northwestern Czech Republic before traversing much of Bohemia , then Germany and flowing into the North Sea at Cuxhaven, 110 km northwest of Hamburg...

 river via the river Jeetzel

Jeetzel

The river Jeetzel, which begins in the Altmark under the name Jeetze, flows from Saxony-Anhalt through Lower Saxony, in Germany. From its source near the village of Dönitz, it flows north through Beetzendorf, Salzwedel, Wustrow, Lüchow and Dannenberg, before joining the Elbe in Hitzacker...

. The water body (0.147 bill. m³) only changes every 100 years. The town Arendsee

Arendsee

Arendsee is a municipality in the Altmarkkreis Salzwedel, Saxony-Anhalt, Germany. It is named after the lake Arendsee, located north of the town.-Geography:...

 and the municipality Schrampe

Schrampe

Schrampe is a village and a former municipality in the district Altmarkkreis Salzwedel, in Saxony-Anhalt, Germany. Since 1 January 2010, it is part of the town Arendsee....

are situated on its shores.