Sheehan is an Irish surname and given name, derived from the Gaelic sept name "O'Siadhain." It translates to "son of John" in Irish, with 'Siadha' meaning John. The Sheehan clan originally hailed from County Cork but can also be found in other parts of Ireland and around the world today.
"Annually, five individuals named Sheehan were born each year from 1989 onwards."