Dear Karen, the Cogan name has two origins: 1) Wales, de Cogan of Glamorgan accompanied Strongbow (Richard, 2nd Earl of Pembroke) and settled in Cork. 2) Ireland (in full Mac Cogan, from Mac Codaghain, ultimately from Cuchogaidh 'war hound'), of Leitrim, and nothing to do with the previous. So there is no need to assume an Irish origin without documentary proof, especially as there were many Cogans in Yorkshire (possibly originally attracted there from Wales by the mines), e.g.: COGAN, William, alderman of Hull, 1823 COGAN, James, victualler & saddler of Blakestone, Finningley, Doncaster, 1822. Regards, David