is a river in Bavaria
. Its source is located in the Bohemian Forest on the territory of the Czech Republic
. Shortly after the river, which is called Black Regen
) in this section, crosses the border. Close to the small town of Kötzting it is joined by the White Regen
The Regen forms the main valley crossing the Bavarian Forest; many settlements within that mountain range are located along the river. Cities along the Regen river include Cham, Regen and Regensburg. At Regensburg the river meets the Danube.
The total length is 165 km.