Whan
Whan—This name in Ulster is a shortened anglicised form of the Galloway sept name M'Ilwhan, also written McIlchon and M'Conn. M'Ilwhan is mostly found in Co. Down and Galloway; correctly written in Gaelic Mac Giolla-chonn.
Alphabetical Index of Anglicised Surnames in Ireland
See also Woulfe’s Irish Names and Surnames
… and O'Hart's Irish Pedigrees