O'TREHY - TROY
Though not numerous in Ireland the name Troy is not uncommon in Co. Tipperary and surrounding areas. The location of this small sept (which originated in Co. Clare but did not remain there) was in the Clogheen district of Co. Tipperary : their association with that part of the country is perpetuated in the place-name Ballytrehy.
O'Trehy is an older anglicized form of the name in use as late as the seventeenth century, but now very rare: O'Trehy is a phonetic rendering of the Irish O Troighthigh, presumably derived from the Irish word troightheach meaning a foot-soldier.
The name in the 1659 census is spelt Trohy and it appears among the more numerous names in the baronies of Eliogarty and Ikerrin, Co. Tipperary. Another place-name is Castletroy, now a suburb of Limerick. The name was closely associated with that city and appears very frequently in its earlier records. Henry Troy was Provost of Limerick in 1197.
In 1198 the first mayor and sheriffs were chosen : between that date and 1463 no less than twenty-one Troys held one or other of those offices.
Some variant forms of the surname spellings are listed below, beginning with the earliest known old Irish form.