As described in historical dictionaries

An Etymological Dictionary of Family and Christian Names (1857)

(origin: Local) The name of a county and town in Ireland, the plain near the water, from Moi or Moy, Gaelic, a plain, Moy, a river, and ai, a region or territory; the region or tract on the river Moy.

Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.


Patronymica Britannica (1860)

MAYO. See INIatthew and Mayow.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.


Surname type: Location or geographical feature

Origin: English

Region of origin: British Isles

Country of origin: England

Religion of origin: Christian

Language of origin: English

BritishSurnames.uk is a Good Stuff website.