The Magazine Fort is located on St. Thomas Hill within Dublin’s Phoenix Park, just off the Military Road near the Islandbridge gate entrance. Construction on the fort began in 1734 and was completed in 1736. It was extended later in 1801. The building’s purpose was to store gun powder and ammunition for British Government Forces.

When the Duke of Dorset ordered that an ammunition store be built for Dublin the former site of the Phoenix Lodge was chosen. At the time of the fort’s building, many Dubliners were living in poverty. Satirist Jonathan Swift published a verse commenting on the construction: “Now’s here’s a proof of Irish sense, Here Irish wit is seen, When nothing’s left that’s worth defence, We build a Magazine.” 

The fort itself is essentially square, featuring four demi-bastions with concrete pillbox machine-gun posts at angles. It contains original 18th-century magazine chambers, a blast wall, and various buildings (including some that were added in the 20th century). The exterior walls are surrounded by a dry moat. A small barracks and accommodation block was added during the 1801 extension for troops.

There have been two raids on the fort when it was active. The first took place on Easter Monday in 1916. During the Easter Rising, young members of Fianna Éireann raided the fort for arms and attempted to blow it up but the fuses burned out before reaching the ammunition dumps and very little damage was caused.

In 1939, a second raid known as the “Christmas Raid,” was carried out by the Irish Republican Army and resulted in weapons and more than one million rounds of ammunition seized. (Most of it was recovered over the following weeks.)

After the Anglo-Irish Treaty, the fort was transferred in 1922 to the Irish Defence Forces from the British. The Irish Army operated the facility until 1988, when it was transferred to the Office of Public Works, which has undertaken conservation work to preserve the historic fort.