Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.
MAXWELL
As described in historical dictionaries
An Etymological Dictionary of Family and Christian Names (1857)
One Macchus, in the eleventh century, obtained lands, on the Tweed, in Scotland, from Prince David, to which he gave the name of Macchus-ville, since corrupted to Maxwell. Maxwell is Macsual, in Gaelic, from Mac, son, and sual, small, little.
Surname type: From given name or forename
Origin: Celtic
Region of origin: British Isles
Country of origin: Scotland
Religion of origin: Christian
Language of origin: Gaelic