Killyleagh (/ k ɪ l i ˈ l eɪ /; from Irish: Cill Ó Laoch, meaning 'church of the descendants of Laoch') is a village and civil parish in County Down, Northern Ireland.
Con motivo de su enlace matrimonial, la reina Isabel II le otorgó los títulos de duque de Sussex, conde de Dumbarton y barón Kilkeel.  Su título completo es: «Su Alteza Real el príncipe Enrique Carlos Alberto David, duque de Sussex, conde de Dumbarton, barón Kilkeel, caballero de la real orden victoriana».
His youngest son, Prince Harry, Duke of Sussex is Baron of kilkeel. Prince Andrew, Duke of York is The Baron Killyleagh. Some non-royal Barons are somehow related to the royal family, for example Maurice Roche, 6th Baron Fermoy is William's first cousin once removed, through William's late mother, Diana, Princess of Wales , who was the 4th Baron Fermoy 's granddaughter.