The fortifications of Portsmouth are extensive due to its strategic position on the English Channel and role as home to the Royal Navy. For this reason, Portsmouth was, by the 19th century, one of the most fortified cities in the world. The fortifications have evolved over the centuries in response to changes in tactics and technology and the area defended has increased. While the first defences focused on Portsmouth harbour, in step with the fortifications of Gosport, later defensive structures protected the whole of Portsea Island and an increasing distance inland. At the same time, the fortifications of Portsmouth and Gosport became part of the wider fortifications of the Solent. Old Portsmouth, on the southwest corner of Portsea Island, has been walled for much of its history.
Fort George was a military fortification in Niagara-on-the-Lake, Ontario, Canada. The fort was used by the British Army, the Canadian militia, and the United States Armed Forces for a brief period. The fort was mostly destroyed during the War of 1812. The site of the fort has been a National Historic Site of Canada since 1921, and features a reconstruction of Fort George.
Tilbury Fort, also known historically as the Thermitage Bulwark and the West Tilbury Blockhouse, is an artillery fort on the north bank of the River Thames in England. The earliest version of the fort, comprising a small blockhouse with artillery covering the river, was constructed by King Henry VIII to protect London against attack from France as part of his Device programme. It was reinforced during the 1588 Spanish Armada invasion scare, after which it was reinforced with earthwork bastion, and Parliamentary forces used it to help secure the capital during the English Civil War of the 1640s. Following naval raids during the Anglo-Dutch Wars, the fort was enlarged by Sir Bernard de Gomme from 1670 onwards to form a star-shaped defensive work, with angular bastions, water-filled moats and two lines of guns facing onto the river.
Portsdown Hill is a long chalk ridge in Hampshire, England. The highest point of the hill lies within Fort Southwick at 131m above sea level. The ridge offers good views to the south over Portsmouth, the Solent, Hayling Island and Gosport, with the Isle of Wight beyond. The hill is on the mainland, just to the north of Ports Creek, which separates the mainland from Portsea Island, on which lies the main part of the city of Portsmouth, one of the United Kingdom's main naval bases. To the north lies the Forest of Bere, with the South Downs visible in the distance. Butser Hill can be seen on a clear day. The hill is formed from an inlier of chalk which has been brought to the surface by an east–west upfold of the local strata known as the Portsdown Anticline.
Deal Castle is an artillery fort constructed by Henry VIII in Deal, Kent, between 1539 and 1540. It formed part of the King's Device programme to protect against invasion from France and the Holy Roman Empire, and defended the strategically important Downs anchorage off the English coast. Comprising a keep with six inner and outer bastions, the moated stone castle covered 0.85 acres (0.34 ha) and had sixty-six firing positions for artillery. It cost the Crown a total of £27,092 to build the three castles of Deal, Sandown and Walmer, which lay adjacent to one another along the coast and were connected by earthwork defences. The original invasion threat passed but, during the Second English Civil War of 1648–49, Deal was seized by pro-Royalist insurgents and was only retaken by Parliamentary forces after several months' fighting.
Fort Blockhouse is a military establishment in Gosport, Hampshire, England, and the final version of a complicated site. At its greatest extent in the 19th century, the structure was part of a set of fortifications which encircled much of Gosport. It is surrounded on three sides by water and provides the best view of the entrance to Portsmouth Harbour. It is unique in two respects. Firstly, it was built over five centuries from its original construction as a blockhouse in 1431 to the final addition of submarine base structures in the mid-1960s. Secondly, it is thought to be the oldest fortified position in the United Kingdom that is still in active military use though coastal fortification was abolished nationally in 1956, and it has been used only for medical purposes since 2020.
The Device Forts, also known as Henrician castles and blockhouses, were a series of artillery fortifications built to defend the coast of England and Wales by Henry VIII. Traditionally, the Crown had left coastal defences in the hands of local lords and communities but the threat of French and Spanish invasion led the King to issue an order, called a "device", for a major programme of work between 1539 and 1547. The fortifications ranged from large stone castles positioned to protect the Downs anchorage in Kent, to small blockhouses overlooking the entrance to Milford Haven in Pembrokeshire, and earthwork bulwarks along the Essex coast. Some forts operated independently, others were designed to be mutually reinforcing. The Device programme was hugely expensive, costing a total of £376,000 ; much of this was raised from the proceeds of the Dissolution of the Monasteries a few years before.
Camber Castle, also known formerly as Winchelsea Castle, is a 16th-century Device Fort, built near Rye by King Henry VIII to protect the Sussex coast of England against French attack. The first fortification on the site was a small, round artillery tower, constructed by Henry between 1512 and 1514, overlooking the Camber anchorage and the entrance to Rye Harbour. In 1539, increasing tensions with France encouraged Henry to rethink his coastal defence plans, and Camber Castle was rebuilt and extended over the next year under the direction of the Moravian engineer, Stefan von Haschenperg. The results were considered unsatisfactory and further work was carried out from 1542 to 1543, at great expense, to rectify the problems. The result was a large, concentric artillery fort, with a central keep, surrounded by four circular bastions and a circular entrance bastion, built from stone and brick.
Southsea Castle, historically also known as Chaderton Castle, South Castle and Portsea Castle, is an artillery fort originally constructed by Henry VIII on Portsea Island, Hampshire, in 1544. It formed part of the King's Device programme to protect against invasion from France and the Holy Roman Empire, and defended the Solent and the eastern approach to Portsmouth. The castle had a square central keep, two rectangular gun platforms to the east and west, and two angled bastions to the front and rear, and was an early English example of the trace italienne-style of fortification popular on the Continent. The Cowdray engraving of the Battle of the Solent in 1545 depicted Henry VIII visiting the castle. Despite several serious fires, it remained in service and saw brief action at the start of the English Civil War in 1642 when it was stormed by Parliamentary forces.
The Western Heights of Dover are one of the most impressive fortifications in Britain. They comprise a series of forts, strong points and ditches, designed to protect the country from invasion. They were created in the 18th and 19th centuries to augment the existing defences and protect the key port of Dover from both seaward and landward attack; by the start of the 20th century Dover Western Heights was collectively reputed to be the 'strongest and most elaborate' fortification in the country. The Army finally withdrew from the Heights in 1956–61; they are now a local nature reserve.
Fort Amherst, in Medway, South East England, was constructed in 1756 at the southern end of the Brompton lines of defence to protect the southeastern approaches to Chatham Dockyard and the River Medway against a French invasion. Fort Amherst is now open as a visitor attraction throughout the year with tours provided through the tunnel complex
Verne Citadel is a 19th-century citadel on the Isle of Portland, Dorset, England. Located on the highest point of Portland, Verne Hill, it sits in a commanding position overlooking Portland Harbour, which it was built to defend. It later became HM Prison The Verne in 1949.
Pendennis Castle is an artillery fort constructed by Henry VIII near Falmouth, Cornwall, England between 1540 and 1542. It formed part of the King's Device programme to protect against invasion from France and the Holy Roman Empire, and defended the Carrick Roads waterway at the mouth of the River Fal. The original, circular keep and gun platform was expanded at the end of the century to cope with the increasing Spanish threat, with a ring of extensive stone ramparts and bastions built around the older castle. Pendennis saw service during the English Civil War, when it was held by the Royalists, and was only taken by Parliament after a long siege in 1646. It survived the interregnum and Charles II renovated the fortress after his restoration to the throne in 1660.
Gunwharf Quays is a shopping centre located in the Portsea area of the city of Portsmouth in England. It was constructed in the early 21st century on the site of what had once been HM Gunwharf, Portsmouth. This was one of several such facilities which were established around Britain and the Empire by the Board of Ordnance, where cannons, ammunition and other armaments were stored, repaired and serviced ready for use on land or at sea. Later known as HMS Vernon, the military site closed in 1995, and opened to the public as Gunwharf Quays on 28 February 2001 after six years of reconstruction. The landmark Spinnaker Tower, which stands close to the site on pilings in Portsmouth Harbour, was opened on 18 October 2005.
Eastney is a district in the south-east corner of Portsmouth, England, on Portsea Island. Its electoral ward is called Eastney and Craneswater. At the 2011 Census the population of this ward was 13,591.
A gunpowder magazine is a magazine (building) designed to store the explosive gunpowder in wooden barrels for safety. Gunpowder, until superseded, was a universal explosive used in the military and for civil engineering: both applications required storage magazines. Most magazines were purely functional and tended to be in remote and secure locations. They are the successor to the earlier powder towers and powder houses.
Fort Grange is one of the Palmerston Forts, in Gosport, England. After Gomer and Elson forts had been approved in 1852, further consideration led to a decision to fill the gap between them by three more forts, and Grange is the most southerly of the three. Work began in 1858 and it was completed in 1863.
Mersea Fort, also known as Cudmore Grove Blockhouse, was an artillery fort established by Henry VIII on the East Mersea coast in 1543. It formed part of the King's Device programme to protect against invasion from France and the Holy Roman Empire, and defended the River Colne that led to the town of Colchester. It was triangular in shape, with earthwork walls and three bastions to hold artillery. It was demobilised in 1552, but was brought back into use several times over the next century and saw service during the Second English Civil War of 1648. The fort hosted an admiralty court to oversea the local oyster trade, until the dilapidation of the site forced the court to move to the Moot Hall in Colchester in the middle of the 18th century. A new gun battery was built at the fort during the Napoleonic Wars, but the fortification then fell into decline and was extensively damaged by the construction of a sea wall along the coast. The remains of the earthworks were excavated by archaeologists between 2002 and 2003.
Eastney Barracks was a military installation occupied by the Royal Marines and located at Eastney near Portsmouth.
Harry's Walls are the remains of an unfinished artillery fort, started in 1551 by the government of Edward VI to defend the island of St Mary's in the Isles of Scilly. Constructed to defend the harbour of Hugh Town from possible French attack, the fortification incorporated Italianate-style bastions with protective orillons and would have been the most advanced design in the kingdom at the time. It was not completed, probably due to a shortage of funds and the passing of the invasion threat, and only the south-west side remains. In the 21st century, Harry's Walls are managed by English Heritage and open to visitors.
