Guilcagh or Gilco, a parish, in the barony of Upperthird, county of Waterford, and a province of Munster, containing, with a post-town of Portlaw, 921 inhabitants. It comprises 2059 statute acres, as applotted under the tithe act, and is a vicarage, in the diocese of Lismore, forming part of the union of Dunhill; the rectory is impropriate in the corporation of Waterford and the Duke of Devonshire. The tithes amount to £148.7.1. of which £88 is payable to the corporation, £16.7.1. to the Duke of Devonshire, and £44 to the vicar. The church is used as a chapel of ease to Dunhill. There are two private schools, in which about 150 children are educated. Near Coolfin are the ruins of Kilbunny church.