Allanson, Allison, Alison
Allanson, Allison, Alison—These names are reckoned to be anglicised forms of Scottish septs of the McAllans, one sept being a branch of the McFarlanes of Dumbarton County, Scotland, in Gaelic Mac Ailean. The Mac Callions, the chief sept of the Campbells of Argyle, have assumed the name of Allen in some cases.
Alphabetical Index of Anglicised Surnames in Ireland
See also Woulfe’s Irish Names and Surnames
… and O'Hart's Irish Pedigrees