The barony of Castleknock (Irish: Caisleán Cnucha meaning "Cnucha's Castle") is one of the baronies of Ireland. Originally part of the Lordship of Meath, it was then constituted as part of the historic County Dublin. Today, it lies in the modern county of Fingal, Ireland. The barony was originally also a feudal title, which became one of the subsidiary titles of the Viscounts Gormanston.