Dunphy
An Irish surname usually treated as a variant of Donoghue/O'Donoghue, though older English writers also linked it to Humphrey.
The #8,928 most common surname in the United States (2010 Census) — about 1 in every 84,219 Americans shares it.
Etymology
The strongest Irish explanation connects Dunphy with the Gaelic name behind Donoghue/Donaghy, ultimately from a personal name meaning roughly 'descendant of Donnchadh' or 'grandson/descendant of Donnchadh' in older patronymic usage. Some 19th-century English surname writers instead treated Dunphy as a variant of Humphrey, by way of sound change and spelling shift, but that is generally regarded as a secondary or less likely explanation. In practice, the surname is most often handled as an Irish family name with phonetic spelling variation.
History
Matheson lists Dunphy among Irish surnames and places it in the same broad group as Donohue and related forms, supporting its Irish use. The name is well established in Ireland and among Irish-descended families abroad, especially in anglophone countries. Older English scholarship sometimes folded it into the Humphrey family of names, which shows how flexible spelling and interpretation could be in earlier surname studies.
Origin
Regions
Variant spellings
Fun fact
The same surname could be read very differently by 19th-century scholars: one camp saw an Irish patronymic, another heard a spelling variant of Humphrey.
From the historical record
“531 DUNPHY. Eliot. Faircloth. Drummy. 452. Donohue. 109. Eliot.”
— Varieties and Synonymes of Surnames and Christian Names in Ireland