Quick answer: Kelly is one of the most common Irish surnames, usually an anglicized form of Ó Ceallaigh, meaning ‘descendant of Ceallach.’ The best-known line was the Ó Ceallaigh dynasty of Uí Maine in east Galway and south Roscommon.
Browse the Kelly Irish family gifts collection for surname-themed keepsakes, or continue below for the historical background.
What does the Kelly surname mean?
Ó Ceallaigh means ‘descendant of Ceallach.’ Ceallach was an old Irish personal name. Woulfe glosses Ceallach as ‘war’ or ‘contention.’ It was a popular personal name in early Ireland, which is why several separate families formed surnames from it.
Where did Kelly families come from in Ireland?
Patrick Woulfe’s Irish Names and Surnames records Ó Ceallaigh as the name of several distinct families. The most historically prominent was the Uí Maine dynasty, associated with territory spanning parts of modern east County Galway and south County Roscommon. Woulfe also records separate Ó Ceallaigh families in Meath and north Dublin, Derry, Laois, Wicklow, Sligo and Cork. The Breagh family, a branch of the southern Uí Néill, held wide lands in Meath and Dublin until the Anglo-Norman invasion scattered them.
The Uí Maine Ó Ceallaigh dynasty
Uí Maine was a major Gaelic polity in Connacht, and the Ó Ceallaigh family held leading status there for centuries; Woulfe notes that their chief Tadhg Mór Ó Ceallaigh fell at Clontarf in 1014. One famous episode occurred at Christmas 1351 at Knockcroghery, County Roscommon, when Uiliam Buidhe O’Kelly, chief of Uí Maine, invited poets and learned men to a celebrated feast. The Dictionary of Irish Biography notes that the gathering is recorded in the Annals of Clonmacnoise and is associated with the poem Fáilte Uí Cheallaigh, ‘O’Kelly’s welcome.’
Kelly, O’Kelly and related spellings
Historical records can show forms such as Ó Ceallaigh, O’Kelly, Kelly and Kelley. Kelly and O’Kelly are two English forms of the same Irish name, and a family can appear under both in different generations. For family research, follow the spelling actually used in each generation and pay close attention to locality.
Kelly migration and the diaspora
Kelly families are widely recorded in Ireland and later in Britain, North America, Australia and elsewhere. For a specific family, civil records, census returns, parish registers, passenger records and local evidence reveal where in Ireland the journey began.
How to research Kelly ancestry
- Start with known birth, marriage and death records and work backward one generation at a time.
- Use the National Archives of Ireland’s 1901 and 1911 census collections to establish households, occupations and exact localities.
- Search IrishGenealogy.ie for civil and church records where available.
- Track townland, parish and county carefully; locality is especially important for a surname borne by several separate Irish families.
Frequently asked questions about the Kelly surname
Is Kelly an Irish surname?
Yes. Kelly is one of the best-known anglicized forms of the Irish Ó Ceallaigh. There is also a separate Scottish territorial history for some Kelly families, covered in our Scottish and Irish Kelly surname overview.
Which counties is Kelly most associated with?
East Galway and south Roscommon, the old Uí Maine country, are the name’s best-known heartland. Woulfe also records Ó Ceallaigh families in Meath and north Dublin, Derry, Laois, Wicklow, Sligo and Cork.
What does Ó Ceallaigh mean?
It means ‘descendant of Ceallach,’ a personal name Woulfe glosses as ‘war’ or ‘contention.’
When was O’Kelly’s famous feast?
The documented Christmas gathering associated with Uiliam Buidhe O’Kelly was held in 1351 at Knockcroghery, County Roscommon.