Helenesee is a lake in Brandenburg, Germany. Its surface area is ca. 250 ha. With a depth of 56.63 m, the Helenseee is the second deepest lake in Brandenburg, only surpassed by the lake Großer Stechlinsee. It is situated approximately 8 kilometers in the south of Frankfurt (Oder). It was formed after the flooding of a former open-pit mining which started in 1958.

Helenesee
Helenesee
Location	Brandenburg
Coordinates	52°16′16″N 14°29′15″E / 52.27111°N 14.48750°E / 52.27111; 14.48750
Type	artificial lake
Basin countries	Germany
Max. length	ca. 2.5 km (1.6 mi)
Max. width	0.9 km (0.56 mi)
Surface area	ca. 250 ha (620 acres)
Max. depth	56.63 m (185.8 ft)