McClain
An Irish and Scottish surname typically understood as a form of McLean, meaning “son of the lean, slender one.”
The #722 most common surname in the United States (2010 Census) — about 1 in every 6,410 Americans shares it.
Etymology
McClain is usually treated as an Anglicized spelling of Gaelic Mac Lean / Mac Gille Eoin-type forms, though in practice it is often linked most directly with McLean. The core sense is “son of Lean” or “son of the lean/slender one,” with lean here likely beginning as a nickname or personal byname. In older records, spelling was highly fluid, so McClain and McLean could overlap in use.
History
The surname is found especially in North America in communities of Scottish and Irish descent, where variant spellings became fixed over time. Nineteenth-century surname lists often grouped McClain with other Mac/Mc names rather than treating it as a fully separate family name, reflecting the spelling instability of the period. In the United States it is now established as a common independent spelling, even where its deeper origin is shared with McLean.
Origin
Regions
Variant spellings
Fun fact
McClain is one of several spellings that can trace back to the same Gaelic surname family, which is why it so often appears near McLean in old alphabetical surname lists.
From the historical record
“McCartney, McCaskill ; McCauley, McCauly, and McCawley ; McCauliffe, McCausland, McCaw, McChesny, McClain, McClannin, McClarren, ^McClearn, McCleary, McClelland, McClenathan, McClenigan, McClennan and McClennen, McClin, McClintock, McClone, McCloskey and McCluskey, McClure, McCol.gan and McColigan, McCollum…”
— Suffolk Surnames (3rd ed.)