It is located at the southern end of the village of Summer Cove, on Kinsale harbour, County Cork, Ireland.

[3] Charles Fort was built on the site of the ruins of an earlier stronghold known as Barry Óg Castle, at Rincurran.

The new fort, which is named after Charles II,[6] was designed by the Surveyor-general Sir William Robinson - architect of the Royal Hospital Kilmainham.

With a focus on seaward defence, the landward and inland bastions of the fort are overlooked by higher ground.

[7][10] John Churchill, 1st Duke of Marlborough (then 1st Earl) besieged Cork and captured Kinsale and its forts.