Tully
A surname with several possible roots, including an Irish name meaning “flood” and a French place-name connection.
The #3,911 most common surname in the United States (2010 Census) — about 1 in every 33,999 Americans shares it.
Etymology
This surname has more than one proposed origin. One line of explanation derives it from Irish forms such as Tuile or O’Tuile, from Irish tuile meaning “flood”; another links it to Irish O’Tuithligh, associated in older sources with a word for a surgeon. A separate, non-Irish explanation connects it with the French place-name Tully in the Somme, traced to a Latin/Gallo-Roman estate name meaning “Tullius’s estate.”
History
The name appears in both Irish and Anglo-French contexts, which helps explain why it has several overlapping etymologies in older surname dictionaries. In English records, related spellings such as Tulley and Tulley are also found. Some 19th-century writers even proposed a folk-etymology from St. Olave’s, but that view is usually treated as doubtful.
Origin
Regions
Variant spellings
Fun fact
Older surname books disagree sharply on whether Tully is mainly Irish or French, so it is a classic example of a surname with more than one independent source.
From the historical record
“(and Ir.) tulacK] TULLY (A.-Fr.-Lat. -|- Celt.) Bel. to Tully (Somme) = TuLLius's Estate [M.Lat. *TuUiacum:dc-um, the Lat.-Gaul. possess. suff.] (Celt.) I the Ir. Tuile—MacTuile, O'Tuile [cp. Ir. tuile, a flood] 2 the Ir. Tdithliagh — O'Tdithligh [Ir. tdithlia{i)gh, a surgeon]”
— Surnames of the United Kingdom: a concise etymological dictionary (2 vols in 1)