Troy, ó Troighthigh Both a Gaelic surname and a surname of Cambro-Norman origin. de Troye, of Troyes formerly the capital of Champagne in France. The sept name derived from Troightheach meaning a ‘foot-soldier’, their original territory was in or near Corcomroe in north-west Clare. However they dispersed to Offaly, North Tipperary, Limerick and Cork, and were know as O’Treahy. In 1890 Troy was principally found in Offally, Cork and Tipperary, and the estimated number of bearers was 1,390.