Of Irish origin.
From an ancient Irish surname.
From a diminutive associated with “fionn”, which derives from the Gaelic “Mag Fhionnain”, meaning “the descendant of the fair one”.
Fionn means “fair”, “blond”, “white”.
It may also mean “son of Fionnán”, therefore somewhat associated with the name Fionn.
It is recorded in several spellings, such as M’Gynnan, M’ Geanayne, MacGannon, Gonning.
According to several sources, it is associated with Norsemen or Danes from the 9th century when part of Ireland was a Viking kingdom.
Mag Fhionnain is an ancient Irish clan from the Erris town, in County Mayo.
Alternative spellings of the name are recorded in England too. These associate Gannon with the pre 7th-century Anglo-Saxon female name “Gunnhildr”.
Gannon has climbed considerably in the U.S.A. popularity lists, from #959 in 2002 to #413 in 2014 and was ranked #706 in 2016.