Wikipedia
O'Boyle
Boyle / O'Boyle is a surname of Irish origin. It is anglised from the Gaelic Ó Baoighill/Ó Baoill.
The clan was founded by a Donegal chieftain, Aneisleis Ó Baoighill, the grandson of Baoghal.
The derivation of the Gaelic/Irish is uncertain, and has been translated as "Peril" or "Danger", "Son of the rash one" or more positively "having profitable pledges" (from the Irish word geall, meaning "pledge").
Their chiefs came to rule over Tír Ainmhireach1 in the west of what is now County Donegal, which as a result became known as Críoch Bhaoigheallach; later renamed as the barony of Boylagh under colonial rule.2