Shannon
An Irish surname that may come from the river Shannon, but in many cases is probably an Anglicized form of an older Irish name.
The #752 most common surname in the United States (2010 Census) — about 1 in every 6,690 Americans shares it.
Etymology
The name is often linked to the River Shannon in Ireland, whose name is usually explained as coming from Irish sean meaning “old” plus abhann/abhan meaning “river,” giving the sense “old river.” However, historical surname evidence also points to Shannon as an Anglicized form of Irish names such as Ó Seanáin or Shanahan in some families. Because the same spelling can have more than one origin, the surname is best treated as having multiple possible Irish pathways.
History
Nineteenth-century writers already disagreed about whether the surname mainly came from the river name or from an older Irish family name. In practice, Shannon is common in Ireland and among Irish diaspora families, especially in English-speaking countries. The surname spread widely through migration to Britain, North America, Australia, and elsewhere.
Origin
Regions
Variant spellings
Fun fact
The river name Shannon has long been glossed as meaning “Old River,” making this one of the more picturesque Irish surnames.
From the historical record
“SHANNAN\(Celt.) i = Shann (q.v) + the SHANNON J Ir. dim. suff. -dn [Ir. Seanan] 2 for Shanahan, q.v. The Irish river-name Shannon app. means 'Old River' [Ir. sean, old + abhan{n, river] SHAPCOTT (Eng.) Dweller at the Sheepcote \0.'E..sc{e)dp + coi\”
— Surnames of the United Kingdom: a concise etymological dictionary (2 vols in 1)