KILROY
Kilroy is a surname of Gaelic origin, found principally within the Irish and Scottish parts of the British Isles. It derives from the Gaelic Mac Giolla Ruaidh, a patronymic construction that literally means son of the red‑haired servant. The name was originally a nickname applied to a person with red hair who worked as a servant or attendant, and over time it became a hereditary family name passed down through successive generations.
The earliest recorded appearance of the name dates to the late fourteenth century, when a Michael M'Gilrey is listed in the Ancient Charters of the Earldom of Morton (1376) during the reign of King Robert XI of Scotland. By the fifteenth century the name was prominent enough to be mentioned repeatedly in the Annals of the Four Masters and the Annals of Loch Ce, testifying to the influence of the McElroys in Gaelic Ireland. The sept of Kilroy originated in County Fermanagh, where the placenames Ballymackilroy (County Fermanagh), Ballymackilroy (County Tyrone) and Ballymacilroy (County Antrim) record the extent of the family’s ancient territory across the east side of Lough Erne.
The surname has generated numerous orthographic variants that reflect changes in spelling practice over the centuries. These include McGilroy, McElroy or McElrea with the initial “Mc”, as well as shorter forms such as Gilroy and the modern Kilroy. Other recorded spellings are McAlroy and McElree, all arising from the same Gaelic root. The use of the prefix Mac or its uncleaved form M' is a common feature of hereditary surnames in Irish tradition, signalling “son of” in the patronymic system.
Significant individuals bearing the surname illustrate its historical reach. Rev. John McElroy, S.J. (1782‑1877), was a native of County Fermanagh who was educated at a hedge school, joined the United Irishmen in 1798, and later became famous as a missionary priest and church builder in America. In the mid‑nineteenth century, Mary McElree was recorded in Maghera, County Derry, and James McElrea was documented at Cappagh by Omagh, County Tyrone. Mrs. Ellen McElroy, age 51, together with her four children, departed from Liverpool aboard the Ohio on 13 March 1846, bound for New York, as famine emigrants.
In the twentieth century, the name acquired an additional layer of cultural resonance through the popular phrase “Kilroy was here”. This emblem became globally recognisable as a graffiti mark left by United States soldiers during the Second World War, reinforcing the surname’s visibility outside Ireland. Today, Kilroy is found in sizable numbers in Ireland, the United Kingdom, the United States (especially Massachusetts and New York), Canada (notably in Ontario and parts of Quebec), Australia, and other former British colonies, a distribution that reflects the pattern of Irish emigration over the last five centuries.
Typical given names associated with the Kilroy surname
Male
- Anthony
- Christopher
- David
- James
- John
- Kevin
- Mark
- Michael
- Stephen
- Thomas
Female
- Anne
- Carol
- Catherine
- Elizabeth
- Emma
- Helen
- Janice
- Margaret
- Mary
- Melanie
- Patricia
- Rachael
- Sarah
- Susan
Similar and related surnames
Related and similar names are generated algorithmically based on the spelling, and may not necessarily share an etymology.
How to communicate the surname Kilroy in...
Braille
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Morse
-.-...-...-.----.--
Semaphore
There are approximately 1,092 people named Kilroy in the UK. That makes it roughly the 6,900th most common surname in Britain. Around 17 in a million people in Britain are named Kilroy.
Surname type: From name of parent
Origin: Celtic
Region of origin: British Isles
Country of origin: Ireland
Religion of origin: Christian
Language of origin: Gaelic
