Tsimlyansk Reservoir or Tsimlyanskoye Reservoir (Russian: Цимля́нское водохрани́лище) is an artificial lake on the Don River in the territories of Rostov and Volgograd Oblasts at (47°50′N42°50′E). Completed in 1952, the reservoir is one of the largest in Russia, providing power and irrigation to the Rostov and Volgograd regions.