The Fort was built in 1734 – 1736 to the design of John Corneille, to store gunpowder and ammunition for British Government Forces. One third of the British Army was stationed in Ireland and was regularly rotated around the Empire. The Fort was raided on two occasions – Easter Monday 1916 and 23 December 1939. The Fort is strategically sited on St. Thomas Hill, off the Military Road, close to the Islandbridge Gate.