Fox
Fox—This name is the anglicised form of several Irish sept names. The most prominent of these are O'Caherney (O'Catharnaigh) or "An Sionnach," i.e., "The Fox," an old Sept in Meath and Longford. The O'Caherneys were chiefs of the ancient district now known as the barony of Kilcoursey, in King's Co., and were originally of the line of Maine, the first chief of Taffia, and fourth son of Niall of the Nine Hostages. The Fox family of Fox Hall, Co. Longford, claims descent from Teige "Sionnach" O'Catharnaigh. In 1568, Sir Patrick Fox of Moyvore, in Westmeath, was Clerk and Interpreter of Irish to the State.
This Sept also occupied the barony of Kilkenny West in ancient Taffia in early times, but later confined to Muintir-Tadhgain, now barony of Kilcoursey. It is hard to say when the Sept assumed the name of "The Fox," but it only stands as a sobriquet, in the same way as the Scottish names, Cameron (from Cam, crooked, and sron, nose—i.e., Wry-Nose—the chief family of that clan being McSorley and McGillonie).
However, the first of the name we meet with in Irish records is above, Teige (Sionnach) O'Catharnaigh, who was killed in battle in 1084. Later we find Neal Sinnach, killed at the Battle of Athenry in 1316, during the reign of Edward Bruce, as King of Ireland, whether he was fighting on the side of the Scots-Irish army, or on that of the Anglo-Normans, I am unable to tell. The Ulster sept that has anglicised the name Fox, is the South Tyrone sept of Mac An t-Sionnaigh, also found anglicised in the district of Eglish, Dungannon; in Tyrone, as McAtinny; Tinney in Donegal, and McAshinagh in Fermanagh and in most parts of N.W. Ulster. I know two brothers at Dungannon, one lives in the country, and is known by no other name than McAtinny; the other lives in town and is known by the name of Fox. I am acquainted with two other instances in the case of M'Gronan and Reynolds, M'Crory and Rogers. There are numerous instances of this in the Five States of Ireland. The name McShanaghy, in the districts surrounding Bawnboy, Co. Cavan; Shanaghy in the district of Ballinagh in the same county, and in Granard district, Co. Longford; Shanaghan in the districts of Mullingar, Cavan Town, Tuam and Gort, Co. Galway; Shinnagh in North Sligo; Shonnagh in the district of Oughterard, Co. Galway; Shunny in the district of Mullinahone, Co. Tipperary; Shunnagh in Gort, Co. Galway; Shannon and Shanan in South Wexford, and Giltinane in South Clare have interchanged to Fox, the foregoing names respectively, are, which number five, Mac Seanchaidhe, O'Seanacháin, (O'Seanáin, O'Seanaigh, and Mac Giolla t-Seanain.