CAHILL (MacCathail) CAHILL IS ONE OF THE EARLIEST RECORDED SURNAMES. ORIGINALLY A FIRST NAMES. CATHAIL IS THE IRISH OF CHARLES WHICH SIGNIFIES 'VALOUR'. THE FIRST TO SEAR THIS NAME WAS AN IMPORTANT SEPT IN SOUTH GALWAY IN EARLY TIMES.SEVERAL DEVELOPED SEPTS WHO DEVELOPED INDEPENDENTLY SPREAD TO MUNSTER, WHERE THERE ARE NO LESS THAN THREE BALLYCAHILLS IN CO. TIPPERARY. THERE IS ALSO A BALLYCAHILL IN CO. GALWAY AND ANOTHER IN CO. CLARE, THEIR ORIGINAL TERRITORY. THANKS FOR LOOKING!