Ó Brosnacháin
Ó BROSNACHÁIN—I—O Brosnaghane, O Brosneghan, Brosnahan, Bresnihan, Brosnan, &c.; 'descendant of Brosnachán' (native of Brosna, in Kerry); the name of an old Kerry family, now also numerous in Co. Limerick.
Alphabetical Index to Irish Surnames