Mac Conleitreach
Mac CONLEITREACH—IV—(?) Letter, Letters; 'son of Cú-Leitreach' (hound of Leitir, a place-name); the name of an old family in Tirawley, Co. Mayo. They were seated at Ballykinletteragh, in the parish of Kilfian, but the name has long since disappeared from that district. It is not improbable, however, that it is the origin of Letters or Letter in other parts of Ireland.
Alphabetical Index to Irish Surnames