Portsmouth Harbour
Coordinates: 50°49′24.60″N 1°7′22.08″W / 50.8235000°N 1.1228000°W
Portsmouth Harbour is a large natural harbour in Hampshire, England. Geographically it is a ria: formerly it was the valley of a stream flowing from Portsdown into the Solent. The city of Portsmouth lies to the east on Portsea Island, and Gosport to the west on the mainland. At its north end is Portchester Castle, of Roman origin and the first fortress built to protect the harbour.
The mouth of the harbour provides access to the Solent. It is best known as the home of the Royal Navy, HMNB Portsmouth. Because of its strategic location on the south coast of England, protected by the natural defence of the Isle of Wight, it has since the Middle Ages been the home to England's (and later Britain's) navy. The narrow entrance, and the forts surrounding it gave it a considerable advantage of being virtually impregnable to attack from the sea. Before the fortifications were built the French burned Portsmouth in 1338. During the civil war parliamentary forces were able to carry out a successful cutting-out expedition within the harbour and capture the six-gunned Henrietta Marie.
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