About Irish Surnames

The full form of most Irish surnames includes an ‘O’ or a ‘Mac’, meaning grandson of, or son of. These are Gaelic surnames, denoting members of the original Irish population whom we now know, from DNA studies, to have arrived on the island 9,000 years ago. Most Irish surnames belong to this category. Then there are Irish surnames of Anglo-Norman origin, amounting to perhaps 7% of the total. These arrived in Ireland in the 12th and 13th centuries from Britain and France as part of a colonial settlement. Finally we have the ‘New English’ surnames, those which arrived from Britain in the 16th and 17th centuries as part of a policy of deliberate plantation. Such surnames amount to over 20% of the modern total. Ireland is remarkable for the great lack of population movement until very recently. Searches of 19th and 20th century records illustrate this. Most of the O’Sullivans remained in Cork and Kerry while most of the Maguires remained in Fermanagh. Surnames have very long associations with the same district. This is true even of the Anglo-Norman ones, such as the Burkes, most of whom remained in Galway, Mayo and Tipperary.

The Brick Wall and Surnames:

When the mainstream genealogical sources ‘hit the brick wall’ there are other approaches to take, such as researching land and estate deeds and rental rolls. Failing this we can consider your very surname as a genealogical resource. Ireland as a society was population static for a thousand years: you will still find people bearing the same surnames located in the same areas in the nineteenth century as their ancestors did in the eleventh century.Therefore surname research is another way to access records of your ancestors, and this can be strengthened further by also using DNA records.

Irish Surname History Research Service

Your Surname Research Starts Here

Where do you go when you’ve finished your Irish family genealogy research? Or when your stuck in your research. Is there more? What about the history of your Irish surname?

A surname is the oldest and most treasured family heirloom, allowing the possibility of viewing the history of ones ancestors well beyond the period recorded by genealogical records. Surnames history study requires specialist expertise, while surname origin and distribution research can add greatly to your family history, as can surname meanings. The following services are offered:



  •  Surnames history overview
  •  Detailed surname histories in book or booklet form
  •  Surnames distribution as a genealogy tool
  •  Surnames research as a tool for yDNA surname studies
  •  Research and lecturing for clan associations and gatherings
  •  Guest lecturing on genealogy and heritage subjects
  •  Sample short and long studies available on request, as published in Irish Roots, Irish Genealogist, and Irishlivesremembered



O’Sullivan Surname

As part of my service to those interested in their Irish surnames I’m going to make available at a modest cost a series of DVD’s giving a full account of the histories of the major Irish clans and surnames. This will be based on the latest and most up to date research, beginning with the remote origins as found in the ancient Irish genealogies. A detailed account will follow, illustrated by maps, pedigrees, coats of arms, and photos of the main castles and other sites associated with each surname. As a leading Irish surname expert, medieval historian, and talented public speaker I can deliver a product that will fascinate, charm and humble those interested in the real stories of their Irish ancestors.

O’Sullivan Surname video is now available 

The first offering concerns the O’Sullivan clan (click to view). This DVD consists of a video recording and a pdf file containing maps, pedigrees and photographs. The video was filmed at the recent O’Sullivan clan gathering in Sneem, Co. Kerry, where the climax of the week was my talk on O’Sullivan clan history, attended by nearly one hundred O’Sullivans and friends from all over, and which lasted for about one hour.

To order please use contact us form or follow this link