Hill
Hill—This name in Ulster is the anglicised form of O'Boyle (O'Baoghail) in many instances in the north-west districts in particular. Bole and Boal are forms of the name in the north-eastern districts.
Alphabetical Index of Anglicised Surnames in Ireland
See also Woulfe’s Irish Names and Surnames
… and O'Hart's Irish Pedigrees