Dalcassian immigrants from Spain to Ireland. Also O'Hogan, O'Hagan, Regan, O'Regan etc. (Source, Matthew Culligan, New York.)
Hogan Name Meaning
Irish: Anglicized form of Gaelic Ó hÓgáin ‘descendant of Ógán’, a personal name from a diminutive of óg ‘young’, also ‘young warrior’. In the south, some bearers claim descent from an uncle of Brian Boru. In northern Ireland a surname of the same form was Anglicized as Hagan.