In physical geography, endorheic lakes are lakes that have no outflow to the sea or ocean.

Endorheic lakes, which generally lie in endorheic basins, are usually found in hot desert areas where the net inflow is low (due to low rainfall) and loss to solar evaporation high. This process often leads to the concentration of salts and other minerals in the lake. The high concentration of salt in the water of some of these lakes can make it possible for a person to float without effort.

In many cases the rivers that feed the lakes are highly seasonal, causing the water level to change dramatically over the course of a year. Some become entirely dry for a portion of the year. Other endorheic basins are permanently dry, either due to historical climate changes or the redirection of river water by human activity.

Dry endorheic basins often contain an extensive salt pan (alkali flat) or playa. These areas, which tend to be large, hard surfaced, and fairly flat, are sometimes used for aviation (as large cheap runways) or for breaking the land speed record.

Examples of endorheic lakes include the Aral Sea in Central Asia, Lake Eyre in Australia, the Dead Sea in the Middle East, and the Great Salt Lake and Pyramid Lake in the US.

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