BADEN, or BADEN-BADEN, a town and celebrated watering-place of Germany, in the circle of Middle Rhine and Grand Duchy of Baden. It stands on the Oos, in a valley of the Black Forest, 18 miles S.W. of Carlsruhe; and it is connected by a branch with the Mannheim and Basle railway. Baden during the months of July and August is frequented by great numbers of visitors from all parts of Europe, so that its resident population, which is only about 6000, is frequently augmented to three times that number. There are thirteen hot springs, varying in temperature from 37° to 54° R., = 115° to 156° F.; and the water is conveyed through the town in pipes to supply the different baths. The superiority of its situation, its extensive pleasure-grounds, gardens, and promenades, render Baden one of the first watering-places in Germany. It was for six centuries the residence of the margraves of Baden. The "old castle" occupying the summit of a hill above the town, was the earliest residence of the reigning house; and the "new castle" (so called by comparison), situated close to the town, is remarkable for its subterranean dungeons. Baden has a library and reading-room, theatre, assembly rooms, and the other accessories of a fashionable watering-place. The parish church contains monuments of several of the margraves. The springs of Baden were known to the Romans under the name of Aurelia Aquensis, and fragments of ancient sculpture are still to be seen there. In 1847 remains of Roman vapour baths, well preserved, were discovered just beneath the new castle.