The name of Bardsey is first attested in the Domesday Book of 1086 as Berdesei and Bereleseie, situated in the hundred of Skyrack.[4] The second element comes from the Old English word ēg ('island') and the first is agreed to be from a personal name. Exactly what this name was is not certain, but the name Beornrǣd is a plausible candidate. Thus the name probably once meant 'Beornrǣd's island' (or the island of someone of a similar name). Since the site is not in fact an island, it has been suggested that the name was metaphorical, referring to a hill rising, island-like, from flat ground.[5]: 20
The name of East Rigton is likewise first attested in the Domesday Book, as Riston, Ritone, and Ritun. The name comes from the Old Norse word hryggr ('ridge'), which had come into more general use in Old English, and the straightforwardly Old English word tūn ('farmstead, estate'). The additional element east is first attested in 1530, in the form Est Ryghton.[5]: 43