Dillon
An Irish surname best known from a noble family in Ireland, though its deeper origin is uncertain.
The #683 most common surname in the United States (2010 Census) — about 1 in every 6,118 Americans shares it.
Etymology
The name is most securely linked in historical surname books to the Irish O'Diolmain / O'Duilleain forms, though the old sources do not agree on a single explanation. One 19th-century writer also suggested a Welsh origin from a word meaning handsome, brave, or fine, but that derivation is less certain and may reflect older speculation rather than a settled fact. In short, Dillon is usually treated as an Irish family name whose exact root is not fully agreed upon.
History
Lower notes Henry Dillon, ancestor of the Irish noble Dillons, as settling in Ireland in 1185 and receiving lands in County Westmeath. The surname became strongly associated with that family and with the area later called Dillon's Country. It also appears in Irish surname traditions in forms such as O'Diolmain and related spellings.
Origin
Regions
Variant spellings
Fun fact
The old surname books specifically connect the Dillon lineage with land around Drumraney, later known as 'Dillon's Country.'
From the historical record
“DILLMAN. See DiUer. DILLON. The common ancestor of the noble Dillons of Ii'eland was Henry Dillon, who settled in that country in the year 1185. King John, while Earl of Mortain, gave him immense tracts of laud about Drumrany, wliich were afterwards collec- tiA'ely known as Dillon's country. See Geneal. Hist, of…”
— Patronymica Britannica: a dictionary of the family names of the United Kingdom