Baden-Baden is a spa town, located in the state of Baden-Wurttemberg in southwestern Germany. It lies at the northwestern border of the Black Forest mountain range on the small river Oos, just 10 km east of the Rhine, the border line to France, and about 40 km north-east of Strasbourg, France. Baden-Baden lies in a valley of the Northern Black Forest in southwestern Germany. The western districts lie within the Upper Rhine Plain. The highest mountain of Baden-Baden is the Badener Hohe, which is part of the Black Forest National Park. The old town lies on the side of a hill on the right bank of the Oos.