Karlsruhe is the third-largest city of the German state of Baden-Württemberg, after its capital Stuttgart and Mannheim, and the 22nd-largest city in the nation, with 308,436 inhabitants. It is also a former capital of Baden, a historic region named after Hohenbaden Castle in the city of Baden-Baden. Located on the right bank of the Rhine near the French border, between the Mannheim-Ludwigshafen conurbation to the north and Strasbourg to the south, Karlsruhe is Germany's legal center, being home to the Federal Constitutional Court, the Federal Court of Justice and the Public Prosecutor General.

Baden-Baden is a spa town in the state of Baden-Württemberg, south-western Germany, at the north-western border of the Black Forest mountain range on the small river Oos, ten kilometres east of the Rhine, the border with France, and forty kilometres north-east of Strasbourg, France.