McLaughlin and McLoughlin are closely related Irish surname spellings that come from Mac Lochlainn, meaning “son of Lochlainn.” The names have especially strong historical connections with Ulster and Inishowen in County Donegal. Before the thirteenth century, the Mac Lochlainn kings seated in Inishowen were the most powerful family in Ulster.
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What does McLaughlin or McLoughlin mean?
Patrick Woulfe records Mac Lochlainn as a Gaelic surname meaning “son of Lochlainn.” His surname dictionary lists anglicized forms including MacLochlin, MacLoghlin and MacLoughlin. Woulfe also records Mac Lachlainn with forms including MacLaughlin, reflecting another closely related spelling tradition found in Ulster and Scotland.
Today McLaughlin is the usual form in Ulster, especially in Donegal, Derry and Antrim, while McLoughlin is more frequent in Connacht and Leinster. Lochlainn itself is a name of Norse origin.
The Mac Lochlainn dynasty of the north
One important Mac Lochlainn dynasty belonged to Cenél nEógain, a major branch of the northern Uí Néill. This family was powerful in medieval Ulster and closely associated with Inishowen and Ailech. The Dictionary of Irish Biography records Muirchertach Mac Lochlainn, who died in 1166, as king of Ailech and a dominant claimant to the high-kingship. A later Domnall MacLoughlin, who died in 1241, is described as the last Mac Lochlainn king of Ulster; his defeat by Brian Ó Néill that year passed leadership of Cenél nEógain to the O’Neills.
These medieval figures place the Mac Lochlainn name in the political history of Ulster. Civil, church and census records trace the later histories of individual McLaughlin and McLoughlin families.
Why the Meath “Melaghlin” story needs care
Different Gaelic surnames sometimes produced similar English spellings. Woulfe separately records Ó Maoilsheachlainn, the surname associated with the historic Meath dynasty often rendered O’Melaghlin or similar forms. Woulfe notes that this name is now also anglicized MacLoughlin, and by the eighteenth century O’Melaghlin had largely given way to MacLoughlin in Meath. That line descends from the tenth-century high king Máel Sechnaill II.
For genealogy, place, date, religion and parish show which of the two traditions a family belongs to.
Where were McLaughlin and McLoughlin families found?
Both forms appear in Irish records, with particularly useful evidence in County Donegal and the Inishowen area. National Archives census returns from 1901 and 1911 contain households under both McLaughlin and McLoughlin spellings in Donegal. Woulfe notes the name is still common in Inishowen and records a branch that moved to Mayo in the seventeenth century, as well as a Leitrim family who followed the O’Rourkes.
McLoughlin and related forms also occur widely in Connacht and Leinster, while many Ulster McLaughlins descend from the Scottish MacLachlans of Strathlachlan in Argyll.
Common spelling variants
- Mac Lochlainn
- Mac Lachlainn
- McLaughlin
- McLoughlin
- MacLoughlin
- MacLochlin and other historical record forms
Spelling was not always fixed. One family can appear under more than one English form across civil, church and census records, especially after migration.
How to research your McLaughlin or McLoughlin ancestors
Start with the most recent proven generation and work backward. In Ireland, note the county, parish and townland whenever possible. Search both principal spellings, then test older variants if the expected record does not appear.
- National Archives of Ireland: use the 1901 and 1911 census returns to locate households and townlands.
- IrishGenealogy.ie: search civil registrations and available church records.
- PRONI: especially useful for Ulster families, land, wills, church material and records relating to Northern Ireland.
- Local geography: compare neighboring households, sponsors, witnesses and recurring townlands.
For emigrant families in the United States, Canada, Britain or Australia, work backward from destination records to an Irish county or townland before deciding which Irish McLaughlin or McLoughlin line fits.
Sources and further research
- Patrick Woulfe, Irish Names and Surnames (1923), entries for Mac Lochlainn, Mac Lachlainn and Ó Maoilsheachlainn.
- Dictionary of Irish Biography, Royal Irish Academy, entries for Muirchertach Mac Lochlainn and Domnall MacLoughlin.
- National Archives of Ireland — 1901 and 1911 Census.
- IrishGenealogy.ie.
- Public Record Office of Northern Ireland (PRONI).