Surnames in Irish
If the surname contains a prefix such as Ó or Nic or Mac Giolla, leave it out. For example, search for Raghallaigh (not Ó Raghallaigh), Pháidín (not Nic Pháidín), Phádraig (not Mac Giolla Phádraig). If the surname contains an initial mutation, do not remove it: Páidín and Pháidín are not identical.
Surnames in English
If the surname contains a prefix such as O' or Mc, leave it out. For example, search for Reilly (not O'Reilly), Fadden (not McFadden).