Charles Fort is a classic star-shaped fortification and one of the largest military installations in Ireland. It was built between 1677 and 1682, during the reign of King Charles II, after whom it is named, to guard the then British-controlled Kinsale Harbour.  

It saw combat once when in 1690 a Jacobite garrison was defeated after a 13-day siege by the army of William of Orange. It remained a garrison of the British Army until 1921. It was abandoned the following year after being burned by anti-Treaty forces during the Irish Civil War. It became a National Monument under the care of the Office of Public Works in 1973.