The name “Deagan” is one of the many spellings of the English translation of the Irish name “O’Duibhghinn” pronounced as O’Dwigan. The Irish name of this sept simply means descendants of (O’) the black (dubh) headed one(ceann).
The most commonly used spelling , found in Ireland today, at least in Tipperary and surrounding counties is “Deegan”. The largest concentration of Deegans appears to be in Counties Laois (Queens), Ofally (Kings) and Tipperary. There are still ruins of Deegan Castle in County Laois on the main road between Nenagh and Dublin.
There are, however, numerous other spellings of the family name in current use such as Digin, Deighan, Duigan, Duffan and more. In the 1665-1667 “Hearth Money Rolls” for Tipperary are found about 17 different Deagan families with spellings such as Duigan, O’Dwigine, Dugin and Dwygan. On the 1840-1844 list of Persons qualified to serve as Jurors for County Tipperary, N.R. the name is only spelled Deegan. Then on the 1826 Tithe Applotment Book and the 1851 Griffith’s Valuation for the Burgesbeg Townland our ancestors Patrick and Judith Ryan Deegan’s name was spelled Digan and Duigan. On the 1901 census the spelling had settled down to Deegan.
The Reverand Patrick Woulfe, in his scholarly work “Irish Names And Surnames”, Dublin, 1923, states “A marked feature of our Irish name-system was the frequent interchange of names of the same or similar meaning. This was doubtless due to the fact our ancestors paid attention to the meaning no less than the form of their names. Father Woulfe goes on to state that one of the classes of names that are interchangeable is a name and its diminutives. Regional accents and phonetic spellings obviously account for a number of the different spellings.
Rev. Woulfe, in his book, lists the Irish name of O’Duibhgeannain as a diminutive of the the name “O’Dubhceann” the same Black Headed One that the Deagans were descendants of. The Irish “Historical Research Center” also states that the O’Duibhgeannain name means descendants of the Black Headed One. Therefore we are all descendants of the same person. Decendants in the O’Duibhgeannain branch of the family usually have an additional “n” in their name such as Duignan, Dignan, Deignan etc.
Throughout the history of Ireland, at least in the second millennium, there have been numerous distinguished “Descendants of the Black Headed One” The earliest O’Duibhghinn I have found a record of is O’Duibhginn (920 A.D) who was the chieftan of the 12 Townlands of Daighinn, seated in the ancient kingdom of Ui Maine (Hy Many) near Loughrea, County Clare. Loughrea is located approximately 28 miles Northwest of Nenagh and twenty miles East of Galway. This O’Duibhghinn family was , reportedly, originally from Fermoy, County Cork and spread out to Munster, Connact and Leinster. The famous Irish poet, O’Heerin, wrote of O’Duighghinn:
The O’Duibhghinns were renowned as being one of the principal learned families of Gaelic Ireland. They were poets and chroniclers to the leading families and established a bardic school at Castle Fore in Leitrim. One family member, Peregrine O’Duibhghinn (died 1664) was one of the famous Four Masters and contributed to the “Annals Of The Four Masters". Jerome Duigan, born 1710, was one of Ireland’s most distinguished harpists. There are many other notable chieftans, poets, bishops, inventors and military found in Irish history.