What is the oldest Irish surname?

What is the oldest Irish surname? The earliest known Irish surname is O’Clery (O Cleirigh); it’s the earliest known because it was written that the lord of Aidhne, Tigherneach Ua Cleirigh, died in County Galway back in the year 916 A.D. In fact, that Irish name may actually be the earliest surname recorded in all of Europe.

The earliest known Irish surname is O’Clery (O Cleirigh); it’s the earliest known because it was written that the lord of Aidhne, Tigherneach Ua Cleirigh, died in County Galway back in the year 916 A.D. In fact, that Irish name may actually be the earliest surname recorded in all of Europe.