Guild of One-Name Studies
One-name studies, Genealogy
Study: McWilliam
Variants: MacWilliam, MacWilliams, McWilliams
Category: 2 - A study where research using core genealogical datasets and transcriptions is well under way, but currently in some countries only.
DNA website: www.familytreedna.com/groups/mc-williams/
Contact: Mr Aaron McWilliams
Begun in 2018, the study seeks to explore the various origins and subsequent distribution of the McWilliam surname and its variant spellings through the use of both primary and secondary sources, family trees, and YDNA analysis.
MacWilliam, M'William, McWilliams, MacWilliams, M'Williams, McCulliam, McKWilliam, MacUilliam, McUilleim are known variants of the surname McWilliam. Currently, McWilliams is the most common spelling, the "s" being widely adopted outside of Scotland by the mid to late 18th century.
The surname McWilliam(s) is derived from the Gaelic "Mac Uilleam" meaning son of William. Found throughout the Highlands and Galloway region of Scotland from as early as the 12th century, it later became common in Northern Ireland following the Ulster plantation. A large number of McWilliams are recorded in Pender’s census of 1659 in southwest Ireland; however, it does not appear that the name was being used as a fixed surname.