McWilliams
A patronymic surname meaning “son of William,” found in Irish and Manx records as a Mac- surname form of Williams.
The #1,746 most common surname in the United States (2010 Census) — about 1 in every 15,044 Americans shares it.
Etymology
McWilliams is a patronymic surname built on Mac, meaning “son of,” plus the personal name William. In practice it developed as an Anglicized form of Gaelic Mac William or related Mac Uilliam forms, so the literal sense is “son of William.” The surname is therefore a Gaelic-style equivalent of the more directly English Williams/Williamson family of names.
History
The name is recorded in Irish and Manx contexts, and 19th-century writers note it among surnames associated with Gaelic families. One source cites an early 16th-century Galway reference to the McWilliams as part of a group of local families, while another notes the MacWilliams as the parent form behind later Manx surnames such as MacRickard/MacRichards. In modern English-speaking countries, McWilliams is now usually treated as a fixed hereditary surname rather than a transparent patronymic.
Origin
Regions
Variant spellings
Fun fact
A 1518 Galway order singled out the Burkes and McWilliams among groups barred from entering the town, showing the surname’s presence in urban Irish records very early.
From the historical record
“rrjAC UilliAm, Mac William, MacCulliam, MacWilliams, MacOuilliams ; Williamson, Williams, Willison, Wilson,”
— Sloinnte Gaedheal is Gall: Irish names and surnames