Surname Variants in Ireland

1827 map of IrelandSimply put, Irish research is difficult. Beyond missing and incomplete records, there are many obstacles that can frustrate even the most seasoned genealogist. In my opinion, an obstacle that is often overlooked is the variation of Irish surnames.

Recently, I was researching a Crowley family that I theorized had roots in Castletownbere, in County Cork. Despite available parish records, I could not locate this family among the registers. I did locate a very promising Cohane family—however, Crowley and Cohane are very different names, so, I disregarded the connection at first.

As I continued to research these Crowleys in the Riobard O’Dwyer Papers housed at NEHGS, I learned that a branch of the Crowleys had in fact used the agnomen Cohane. An agnomen is essentially a nickname adopted by a family to distinguish itself from other families.

O’Dwyer wrote:

“Tradition has it that the members of the branch of the Crowleys were on their way from the west of Ireland to help the Irish army in the Battle of Kinsale in 1601, but somewhere on the journey a heavy fog descended. It was difficult enough to move through the rough terrain of the time in good weather, but the foggy conditions made any reasonable travelling speed almost impossible, so much so that the Battle was over by the time they arrived. CEO (pronounced KEOW) is the Gaelic for fog, hence this branch name.”1

O’Dwyer’s work lists many variants and agnomens used by West Cork families. Some agnomens are descriptors, like Merigeach, which means freckled, a name employed by the Harrington family. Others describe origins or occupations.

How can you determine if your family’s name is a variant or an agnomen? My advice is to always research the parish or region were your ancestor lived. Are there sources or manuscripts that offer histories of local families? Be sure to check with the local library, too.

Finally, always examine the sources listed below; they provide crucial information regarding surnames. Good luck!



1 Riobard O’Dwyer, “Names and Variants of the Beara Peninsula,” Mss 1097, Box 23, Folder 324, NEHGS, Boston.

Sheilagh Doerfler

About Sheilagh Doerfler

Sheilagh, a native of Chelmsford, Massachusetts, received her B.A. in History and Communication from the University of Massachusetts-Amherst. Her research interests include New England, Norway, Sweden, Ireland, Westward Migration, and adoptions.View all posts by Sheilagh Doerfler