Deegan
An Irish surname most often linked to a Gaelic nickname meaning “little dark one” or “black-haired one.”
The #8,962 most common surname in the United States (2010 Census) — about 1 in every 84,518 Americans shares it.
Etymology
Deegan is generally treated as an Irish surname from Gaelic roots. The most likely explanation connects it with a nickname for a dark-haired or dark-complexioned person, often glossed in older sources as “black-head” or something similar. The spelling has several historical variants, including Deegan, Deighan, Digan, and Duigan.
History
The name is well established in Ireland, especially in the south. The Matheson references point to concentrations in counties such as Waterford, Cork, and Tipperary, which fits its Irish distribution. Like many Irish surnames, it later spread more widely through emigration to Britain, North America, and other English-speaking countries.
Origin
Regions
Variant spellings
Fun fact
One 19th-century Gaelic note glosses Deegan as meaning “black-head,” showing how strongly many Irish surnames were tied to physical nicknames.
From the historical record
“Digan, Deegin, Deighan, Deegan, Duigan ; Dugan, Duggan, Duggen. 0 -Ouibj^iollA. Duffley, Diffily, Diffely. Diffley, Deffely.”
— Sloinnte Gaedheal is Gall: Irish names and surnames