What the historical record says
Stewart is a Scottish surname taken from the office of steward, in particular the High Steward of Scotland, and it became the name of Scotland's royal house. In Ireland it is found overwhelmingly in Ulster, brought over by Scottish settlers during the plantation of the early 17th century. It is not a Gaelic Irish name, and the spellings Stewart and Stuart both descend from the same Scots office-title. It remains numerous across the northern counties.
Recorded Gaelic root: from the Scots office of "steward" (not Gaelic Irish)
Strongest county signals
- Tyroneprocessed surname/place signal
- Downprocessed surname/place signal
What this evidence can—and cannot—prove
Census clustering can show where a surname appeared strongly at a historical point in time. It cannot identify your exact ancestor, prove a clan relationship, or assign a coat of arms. Use it as a source-backed starting point alongside family records and parish research.