KILLAHY, a parish, in the barony of KNOCKTOPHER, county of KILKENNY, and province of LEINSTER, 6 miles (S.) from Knocktopher, on the road from Waterford to Kilkenny; containing 712 inhabitants, and comprising 2670 statute acres. It is a vicarage, in the diocese of Ossory, forming part of the union of Kilbeacon, or Rosinan; the rectory is impropriate in the Ladies Fitzpatrick. The tithes amount to £171, of which two-thirds are payable to the impropriators, and one-third to the vicar. In the R. C. divisions it forms part of the union or district of Kilmacow. About 30 children are educated in a private school.