Padraig Mac Giolla-Domhnaigh

Haggart—This name in Scotland and Ulster is the anglicised form of Mac An t-Sagart, a Ross sept, and also anglicised Target, and Taggairt, but have no common origin with Irish sept in Ulster, the sept of McEntaggart and M'Intaggart, a good number of whom have also become Taggart.

Alphabetical Index of Anglicised Surnames in Ireland

See also Woulfe’s Irish Names and Surnames
and O'Hart's Irish Pedigrees