Low Rock Castle, Portstewart, County Derry

Bence-Jones, Mark. A Guide to Irish Country Houses (originally published as Burke’s Guide to Country Houses volume 1 Ireland by Burke’s Peerage Ltd. 1978); Revised edition 1988 Constable and Company Ltd, London.
p. 195. “A two storey late-Georgian seaside villa, with a bow like a round tower at either end of its front; originally battlemented. The bows contain circular rooms. The birthplace of Field Marshal Sir George White, VC, the defender of Ladysmith. (see also Rock Castle).

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