Ergyng was a Welsh kingdom of the sub-Roman and early medieval period, between the 5th and 7th centuries. It was later referred to by the English as Archenfield.

Archenfield is the historic English name for an area of southern and western Herefordshire in England. Since the Anglo-Saxons took over the region in the 8th century, it has stretched between the River Monnow and River Wye, but it derives from the once much larger Welsh kingdom of Ergyng.