Forts of Kinsale

James Fort and Charles Fort are two historically coastal fortifications guarding Kinsale Harbour in County Cork, Ireland. James Fort (also called “old fort”) occupies the Castlepark peninsula on the western side of Kinsale harbour, downstream on the River Bandon. Charles Fort (also called “new fort”) lies across the harbour at Summer Cove on the opposite side, forming a complementary defence to James Fort.

Prior to James Fort, a medieval fortification occupied the site, and was held briefly by Spanish forces during the Siege of Kinsale in 1601. After the siege, construction of James Fort began in 1602, in the reign of James I. The fort was completed by about 1607. The fort included a half‑bastioned stone central work with pentagonal earthworks and a hexagonal water‑edge blockhouse. During the Williamite War, it was held by Jacobite forces but was captured by Williamite troops in 1690 after its gunpowder magazine exploded. In subsequent centuries, James Fort declined in strategic use and by the 19th century it was already described as a ruin.

On the harbour’s opposite side, Charles Fort was built in the period 1677–1682 on the earlier site of Ringcurran Castle, which had played a role in the 1601 siege. Its design adopted a “trace italienne” or star‑fort layout to better resist cannon fire. During the Williamite War, Charles Fort endured a siege in 1690 by forces under John Churchill; after 13 days it surrendered under negotiated terms. It remained in British military use for about two centuries, until after the Anglo‑Irish Treaty (1921). In 1922, anti‑Treaty forces burned parts of the fort in the Irish Civil War.