HOLY ISLAND, or Holyhead Island, an island in the W of Anglesey; divided, by an isthmus, into the parishes of Holyhead and Rhoscolyn. It extends from NW to SE; measures about 8 miles in length, and about 3½ in maximum breadth; and is separated from the rest of Anglesey by a sandy strait, in some places fordable at low water. The turnpike road and the railway cross the strait on a long causeway or embankment, with an arched water way or bridge in the middle, through which a tremendous current rushes at the turn of the tide. A rocky eminence near Rhoscolyn church commands an excellent view of the island, "rivalling, on a clear day, some of the finest portions of the coasts of Italy." See HOLYHEAD and RHOSCOLYN.

(John Marius Wilson, Imperial Gazetteer of England and Wales (1870-72))