Show ContentsO'Killen History, Family Crest & Coats of Arms

The Irish surname O'Killen originally appeared in Gaelic as Ó Cillin. 1

Early Origins of the O'Killen family

The surname O'Killen was first found in County Mayo (Irish: Maigh Eo) located on the West coast of the Republic of Ireland in the province of Connacht, where they held territories was at Ballykilleen since early times. This lofty family were the ancient Chiefs of Fingal, Earls of Fingal and Lords Killeen.

Saint Kilian, (also spelled Killian) from the Irish: Cillian, (c. 640-689) was an Irish missionary bishop and the apostle of Franconia. He was born in Mullagh, County Cavan, and is the patron saint of the parish of Tuosist, in County Kerry. Saint Kilian's feast day is July 8th and St. Kilian's Abbey, at Würzburg is named after him.

Today there are two Killeen Castles in Ireland: one located at Dunsany, in County Meath, that dates back to about 1180, but today's structure is a restoration of the 19th century after a fire in 1981. It will include a luxury golf course designed by Jack Nicklaus. The second Killeen Castle is a 17th century castle at Killeen, in Castlegar, County Galway.

There are some scanty records of the family in Scotland, but they are rather late: "John Killan in Cleckaime, parish of Lesmahago, 1677, and Robert Killand in Deidwatters, parish of Lesmahago, 1678. This name in Irish is O'Cilleain, descendant of Cillean, a diminutive of Ceallach, an ancient and once very common name." 2

Early History of the O'Killen family

This web page shows only a small excerpt of our O'Killen research. Another 122 words (9 lines of text) covering the years 1172, 1180 and 1981 are included under the topic Early O'Killen History in all our PDF Extended History products and printed products wherever possible.

O'Killen Spelling Variations

Within archives, many different spelling variations exist for the surname O'Killen. Ancient scribes and church officials recorded names as they were pronounced, often resulting in the name of the single person being recorded under several different spellings. Different spellings that were found include Killeen, Killen, Killion, Killian, Killin, Gilin, Killan, Killoon, O'Killen, McKillen and many more.

Early Notables of the O'Killen family

More information is included under the topic Early O'Killen Notables in all our PDF Extended History products and printed products wherever possible.

Migration of the O'Killen family

Irish families fled the English-colonized Ireland in record numbers during the 19th century for North America. Many of those destitute families died from disease during, and even shortly after, the long journey. Although those that immigrated before the Great Potato Famine of the 1840s often were granted a tract of land, those that arrived later were generally accommodated in urban centers or in work camps. Those in the urban centers would labor in the manufacturing sector, whereas those in work camps would to build critical infrastructures such as bridges, canals, roads, and railways. Regardless of when these Irish immigrants came to North America, they were critical for the rapid development of the young nations of the United States and Canada. Early immigration and passenger lists have recorded many early immigrants bearing the name of O'Killen: Jenkins Killen, who settled in Virginia in 1805; Alexander, Denis, James, John, Patrick, and Robert Killen, who all arrived in Philadelphia between 1840 and 1860.



  1. MacLysaght, Edward, The Surnames of Ireland. Ireland: Irish Academic Press, sixth edition, 1985. Print. (ISBN 0-7165-2366-3)
  2. Black, George F., The Surnames of Scotland Their Origin, Meaning and History. New York: New York Public Library, 1946. Print. (ISBN 0-87104-172-3)


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