Ó hEarchadha
Ó hEARCHADHA, Ó hEARCHAIDH—I—O Harroughow, O Harrochoe, O Horrochoe, O Horchoy, O Hurkoy, O Hurowe, Haraghy, Hiraghy, Harrihy, Harkey, Horohoe, Horahoe, Harroe, Hurroe, (Hore, Hoare, Harris, Harrison); 'descendant of Earchaidh' (noble warrior); an old Connacht surname, now variously anglicised, and in Mayo disguised as Harris and Harrison. It was not uncommon in Tipperary in the 16th and 17th centuries, but I have not been able to trace any modern anglicised form in that county.
Alphabetical Index to Irish Surnames