The Schwielochsee is a lake in Lower Lusatia, the south-eastern part of Brandenburg, eastern Germany.

The Spree flows in from the west and leaves the lake to the north in the direction of Beeskow.

The water level is mainly regulated by the Spree River, which flows through the north-western part of the lake.

Even today, numerous erratic blocks of various sizes and rock types bear witness to their Scandinavian origin.

Due to this fact and despite the difficulty of determining its exact origin, the Schwielochsee can be described as a gully lake, which is also evidenced by its elongated and narrow shape.