St., a small episcopal city of North Wales, county of Flint, 20 miles west of Chester, and 208 northwest of London. It is agreeably situated on an eminence near the northern extremity of the fertile vale of Clwyd, between the rivers Elwy and Clwyd, not far from their confluence. The city is small, consisting principally of a single street. It has a cathedral, a church, four chapels, a free grammar-school, Bishop Barrow's almshouse for eight widows, a bank, and a bridge of five arches over the Elwy. Since the passing of the Reform Act, it is a contributory borough to Flint. Pop. of borough in 1851, 2041.

The see is very ancient, having been established in the middle of the sixth century by Kentigern, otherwise called St Mungo, bishop of Glasgow. Driven from the north by persecution, he sought refuge here, and was protected by Cadwallon, who aided him in building a church and founding a college or monastery in this place. Being recalled to his original charge, he nominated as his successor a pious scholar named Asa or Asaph, from whom both the church and town received their designation. Whether Kentigern assumed the title of bishop while here is not known, but there is evidence that Asaph certainly did, and that on his death in 596, he was interred in his own cathedral. The first edifice, which was of wood, was consumed by fire in 1282. A more substantial building was soon afterwards erected by Bishop Anian; and this was nearly destroyed during the wars of Owen Glyndwr. It was partially rebuilt by Bishop Redman about 1480, but the choir remained unfinished till about 1770, when it was completed by the dean and chapter. In the parliamentary wars the edifice was converted into a barrack, and sustained great injury.

The present cathedral is a neat plain cruciform structure, with a square tower 93 feet high rising from the intersection of the nave and transepts. Its length from east to west is 179 feet, its breadth at the transept 108 feet, and at the nave and side aisles 68 feet. The east end is lighted by a large window, an imitation of one at Tintern Abbey, filled with modern stained glass; and several other stained windows have been added at different times. Among its monuments are an altar-tomb supporting a recumbent figure in episcopal robes, in memory of Bishop Dafydd ap Owen, who died in 1502; a full-length figure, in white marble, of Dean Shipley; an altar-tomb recording the decease of Bishop Luxmore in 1830; and a mural tablet in memory of the poetess Felicia Hemans, who, during a great portion of her life, resided in the vicinity.

The episcopal palace is a large modern structure a little to the west of the cathedral, overlooking the Elwy. The parochial church, dedicated to St Asaph and St Kentigern, is situated at the foot of the hill of which the cathedral occupies the summit. The rivers in the neighbourhood abound with fish, and are much resorted to by anglers. There are also some remarkable caverns and other places of interest in the vicinity.

Among the prelates of this diocese may be especially named Bishop William Morgan, an eminent linguist, and the principal translator of the Welsh Bible, printed in 1588; Dr Isaac Barrow, uncle and preceptor of the great mathematician of the same name; Dr William Beveridge, an eminent orientalist and critic, as well as a devout, zealous, and useful theologian; and Dr Samuel Horsley, celebrated as a scholar, mathematician, and theologian.