Baden, Or Baden-Baden (to distinguish it from other places of the name), a town and fashionable watering-place of Germany, in the grand-duchy of Baden, 23 m. S. by W. of Karlsruhe, with which it is connected by a branch of the Mannheim and Basel railway. Its situation - on a hill 600 ft. high, in the beautiful valley of the Black Forest - its extensive pleasure-grounds, gardens and promenades, and the brilliancy of the life that is led during the season, have long attracted crowds of visitors from all parts of the world. The resident population was in 1885, 12,779; in 1895, 14,862; and in 1905, 16,238; but the number of visitors exceeds 70,000 annually. Until the war of 1870, the prevailing nationality was French, but of late years Americans, Russians and English are the more numerous. The hot springs are twenty-nine in number, and vary in temperature from 37° to 54° R., i.e. from 115° to 153° Fahr. They flow from the castle rock at the rate of 90 gallons per minute, and the water is conveyed through the town in pipes to supply the different baths.

There are two chief bathing-establishments, accounted the most elegant in Europe. The waters of Baden-Baden are specific in cases of chronic rheumatism and gout, paralysis, neuralgia, skin diseases and various internal complaints, such as stone and uric acid. The town proper is on the right bank of the Oos, but the principal resorts of the visitors are en the left. A Conversationshaus and a Trinkhalle or pump-room, a theatre and a picture-gallery, library and reading-room are among the chief buildings. The public gaming-tables, which for so many years were a striking feature, are now abolished. The only building of much antiquarian interest, with the exception of the castles, is the parish church, which dates from the 15th century, and contains the tombs of several of the margraves. The churches include a Lutheran, an English, in the Norman style of architecture, and a Russian, with beautiful frescoes; while on the Michaelsberg is the Greek chapel, with a gilded dome, which was erected over the tomb of a son of the Rumanian prince Michel Stourdza, who died here in 1863.

The springs of Baden were known to the Romans, and the foundation of the town is referred to the emperor Hadrian by an inscription of somewhat doubtful authenticity. The name of Aurelia Aquensis was given to it in honour of Aurelius Severus, in whose reign it would seem to have been well known. Fragments of its ancient sculptures are still to be seen, and in 1847 remains of Roman vapour baths, well preserved, were discovered just below the New Castle. From the 14th century down to the close of the 17th, Baden was the residence of the margraves, to whom it gave its name. They first dwelt in the Old Castle, the ruins of which still occupy the summit of a hill above the town, but in 1479 they removed to the New Castle, which is situated on the hill-side nearer to the town, and is remarkable for its subterranean dungeons. During the Thirty Years' War Baden suffered severely from the various combatants, but especially from the French, who pillaged it in 1643, and laid it in ashes in 1689. The margrave Louis William removed to Rastatt in 1706. Since the beginning of the 19th century the government has greatly fostered the growth of the town.

See Wettendorfer, Der Kurort Baden-Baden (2nd ed., 1898); Schwarz, Die Heilquellen von Baden-Baden (4th ed., 1902).