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

In its ancient Gaelic form, the Irish name O'Casey was written Ó Cathasaigh, from the word "cathasach," which means watchful. 1

Early Origins of the O'Casey family

The surname O'Casey was first found in the counties of Fermanagh, Mayo, Dublin, Limerick, Cork and Roscommon. In early times, there were six unrelated septs of Ó Cathasaigh; the two most important were the erenagh (church steward) families of Devenish in the county of Fermanagh and the Lords of the Suaithni, in the present-day barony of Balrothery West, in County Dublin. The name has since become widely scattered. Although it remains common in County Dublin, it is now most prevalent in the southwest of Munster, with a smaller but still sizable population in north Connacht. This corresponds with the locations of the other four septs, which were found at Liscannon near Bruff in the County Limerick; near Mitchelstown in County Cork; in Clondara in County Roscommon; and in Tirawley in County Mayo, where two Casey septs were located. The Caseys of Mayo and Roscommon, like those in Fermanagh, were also notable as erenaghs.

Archaeological remains indicate that Caseys were also once found near Waterford. Furthermore, a sept of MacCasey was once located at Oriel and was common in County Monaghan. However, this sept is nearly extinct today. Due to the widespread dropping of Irish prefixes under British rule and their often-erroneous resumption in the 20th century, many MacCaseys are incorrectly thought to be O'Caseys.

Early History of the O'Casey family

This web page shows only a small excerpt of our O'Casey research. Another 113 words (8 lines of text) covering the years 1172, 1381, 1551, 1723, 1762, 1765, 1773, 1787, 1800, 1801, 1840, 1846, 1848, 1862 and 1870 are included under the topic Early O'Casey History in all our PDF Extended History products and printed products wherever possible.

O'Casey Spelling Variations

Up until the mid twentieth century, surnames throughout the world were recorded by scribes with little regard of spelling. They recorded the name as they thought the surname should be spelt. Accordingly, research into the name O'Casey revealed spelling variations, including Casey, MacCasey, O'Casey and others.

Early Notables of the O'Casey family

Notable amongst the family name at this time was

  • Willet Casey (1762-1848), American-born, Canadian farmer and politician in Upper Canada. Samuel Casey (1723-1773) was a noted silversmith and counterfeiter active in Little Rest (Kingston), Rhode Isla...

Migration of the O'Casey family

North America accepted thousands of Irish immigrants during the 19th century as their homeland suffered under foreign imperialistic rule. Although settlers from the early portion of the century came to North America by choice in search of land, by far the largest influx of Irish immigrants came to North America during the Great Potato Famine of the late 1840s. Many of these Irish families left the country destitute and in some cases suffering from disease. However, those who survived the long ocean voyage were especially vital to the development of industry in the United States and what would become known as Canada. Research of immigration and passenger lists has shown many early immigrants bearing the name O'Casey: Elizabeth Casey who arrived in Maryland in 1725; as well as Andrew, Cornelius, Daniel, David, Edward, James, John, Mary, Michael, Patrick, Richard, Thomas and William Casey, who all arrived in Philadelphia between 1840 and 1865..


Contemporary Notables of the name O'Casey (post 1700) +

  • Breon O’Casey (b. 1928), Irish artist and the son of playwright Sean O´Casey
  • Sean O'Casey (1884-1964), Irish playwright, best known for "Juno and the Paycock" and "The Plough and the Stars"
  • Breon O’Casey (b. 1928), the son of playwright Sean O´Casey, is an artist and craftsman
  • Breon O'Casey (1928-2011), English-born, Irish artist and craftsman, son of Sean O'Casey


The O'Casey Motto +

The motto was originally a war cry or slogan. Mottoes first began to be shown with arms in the 14th and 15th centuries, but were not in general use until the 17th century. Thus the oldest coats of arms generally do not include a motto. Mottoes seldom form part of the grant of arms: Under most heraldic authorities, a motto is an optional component of the coat of arms, and can be added to or changed at will; many families have chosen not to display a motto.

Motto: Per varios casus
Motto Translation: By various fortunes.


  1. MacLysaght, Edward, Supplement to Irish Families. Baltimore: Genealogical Book Company, 1964. Print.


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