where in ireland are callachan from
Callahan Family Name. An Irish surname, Callahan is from the Gaeic term âceallachâ which means rivalry and strife. Another form âceallâ means someone smart, with a bright head. Variations in spelling for Callahan include Ceilahan, Callaghan, Callihan, Callachan, Kallahan, Calahan, OâCallahan, O;Kallaghan, Kelagan and Callighan.