A Henrician artillery castle built between 1541 and 1544 by Henry VIII as part of his network of coastal defences to protect against French and Spanish invasion. Hurst Castle was established to defend the important Needles Passage at the western entrance of the Solent and was designed to withstand both sea and land attack. During the civil war the castle was occupied by parliamentary forces and in 1648 Charles I was held prisoner in the castle. The castle was repaired between 1673 and 1675. The tower was rebuilt around 1805 during the Napoleonic wars, and in the 1850s the castle's dock was built as well as the West Battery (1852). The castle was refortified during further hostilities between England and France in the 1860s, and two large wing batteries were built to house 30 heavy guns. A number of lighthouses were also established at Hurst and represent an important evolution of historical navigation lighting at Hurst which dates from 1786.
The castle continued to be repaired and refortified in the 1890s, and a coastal battery was built in 1893. Soldiers were stationed at Hurst Castle during the Second World War, and wall paintings have been found in the west wing battery which was used as a theatre.
The original Henrician artillery castle had a much more advanced design than the other castles built in this first phase of coastal defences. It was a twelve-sided tower surrounded by a geometric curtain wall with three projecting semi-circular bastions. All of these defences were surrounded by a moat. The castle had various firing lines and was equipped with embrasures for over 70 weapons. The most important repairs to the castle were made in the 1860s when two wing batteries were added. These were designed to house 30 heavy guns and each casemate was built of brick with granite faced elevations to the sea.