Ó Ceallacháin

Ó Ceallacháin, primarily anglicised O'Callaghan as well as variants of Callihan, is an Irish surname. Notable people with the surname include:

Pat O'Callaghan, Irish hammer-thrower
Seán Óg Ó Ceallacháin, journalist, author and broadcaster
Bill Callihan, American football player
Mike Callihan, Lieutenant Governor of Colorado