The Regen (Czech: Řezná) is a river in Bavaria, Germany. Its source is located in the Bohemian Forest on the territory of the Czech Republic. The river, which is called Black Regen (Schwarzer Regen) in this section, soon crosses the border at Bayerisch Eisenstein. Close to the small town of Kötzting it is joined by the White Regen (Weißer Regen).

The Regen Valley forms the main valley crossing the Bavarian Forest; many settlements within the mountains are located along the river. Cities along the Regen river include Cham, Regen and Regensburg. At Regensburg the river joins the Danube.

The river's total length is 165 km.

Rivers of Germany | Tributaries of the Danube

Regen (Fluss)