Bath, city, unitary authority of Bath and North East Somerset, historic county of Somerset, southwestern England. Bath lies astride the River Avon (Lower, or Bristol, Avon) in a natural arena of steep hills. It was built of local limestone and is one of the most elegant and architecturally distinguished of British cities. Its 16th-century abbey church of St. Peter and St. Paul is late Perpendicular Gothic and is noted for its windows, but it is the wealth of classical Georgian buildings mounting the steep valley sides that gives Bath its distinction. The city was designated a UNESCO World Heritage site in 1987.

Medieval Bath, incorporated by charter in 1189, shared in the west-of-England wool trade and later in the cloth trade, but the baths, although still used by royalty, were poorly maintained. When portions of the Roman baths were rediscovered in 1755, Bath had already revived as a spa. In its heyday as a fashionable resort—presided over by the social figure Richard (“Beau”) Nash, one of the greatest English dandies—the Elizabethan town was rebuilt and extended in Palladian style by the architects John Wood the Elder and Younger and their patron, Ralph Allen, who provided the stone from his local quarries and built the mansion of Prior Park (1735–48) overlooking the city. In 1769–74 Robert Adam built Pulteney Bridge to connect Bath with the new suburb of Bathwick across the River Avon.