Irish Surname Origins & Genealogy Resources

Origin of Irish Surnames



Irish Family Names

Irish surnames have Gaelic and Norman roots. In Northern Ireland, English and Scottish names, derived from the Gaelic, can also be found. During the 1600s and 1700s, when Irish names were discouraged, some Irish families adopted English surnames.

Many Irish names have an "O" or "Mc" prefix. "O" means grandson and "Mc" means son. During the 1700s and early 1800s, when the Irish language was dying, there was a gradual dropping of the "O" and "Mc" from names. As awareness of Gaelic heritage was renewed, these prefixes were restored. When searching for Irish names, be sure to check your surname both with and without the prefix e.g. Sullivan and O'Sullivan.
  • Patronymic Surnames
    Suffix mean  "son of"
    Mac, Mc - son of
    O' - grandson of

  • Geographical Surnames
    Suffix Derived from nearby locations. Bally– (town), –more (big), or –beg (small)

Some of the most common Irish surnames in the US:

Boyle

Brennan

Brown

Burke

Burns

Calhoun

Callahan

Campbell

Carroll

Clark(e)

Collins

Conley

Conner

Daugherty

Duffy

Dunn

Farrell

Ferguson / Fergusen

Fitzgerald

Flynn

Gallagher

Hays / Hayes

Hughes
Kelly

Kennedy

Lynch

Martin

McCarthy

McDonald

McGuire

Moore

Murphy

Murray

Nolan

O'Brien

O'Donnell

O'Neil

Quinn

Reilly

Ryan

Smith

Sullivan

Sweeney

Thompson

Walsh

White

To find additional surnames, choose the first letter of surname:
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z