In 1868, the parish of Castleboy contained the following places:
"CASTLEBOY, (or Castlebuoy, or St. Johnstown), a parish in the barony of Ards, in the county of Down, province of Ulster, Ireland, 4 miles to the N.E. of Portaferry. It is situated on the coast of the Irish Channel, on Cloghy Bay, and had a preceptory of the Knights of St. John, founded by Hugh de Lacy, near the close of the 12th century. Ruins of the building still exist. The district is fertile.
[Transcribed from The National Gazetteer of Great Britain and Ireland 1868]
by Colin Hinson ©2018