Killion
An Irish surname most likely connected to the Gaelic name element behind Killen and Killian.
The #6,799 most common surname in the United States (2010 Census) — about 1 in every 62,247 Americans shares it.
Etymology
This surname is usually treated as an anglicized Irish form related to Gaelic names in the Cille-/Cillin- group, which are also behind surnames such as Killen and Killian. The ultimate sense is not perfectly certain from the excerpts alone, but it points to an Irish personal-name origin rather than a place-name or occupation. In practice, Killion is best understood as a surname that arose from the Gaelic naming system and was later rendered in English spelling.
History
The name appears in Irish surname lists alongside Killen and Killian, suggesting close historical and phonetic connections among those forms. Modern bearer numbers in the United States indicate that it survived as a relatively uncommon but established Irish-American surname. The historical sources here do not give a full standalone derivation, so the exact branching from the related forms remains somewhat uncertain.
Origin
Regions
Variant spellings
Fun fact
In older Irish surname compilations, Killion is often listed right next to Killen and Killian, reflecting how easily these names could merge or shift in spelling over time.
From the historical record
“C CilleAin, Killane, , Killan, Killian, Killion. 0 Cillin, Killeen, Killen, Killian Killion. 0 CineAit, Kinna, Kenna, Ken-”
— Sloinnte Gaedheal is Gall: Irish names and surnames