Portland has been inhabited since at least the Mesolithic period (the Middle Stone Age)—there is archaeological evidence of Mesolithic inhabitants at the Culverwell Mesolithic Site, near Portland Bill,[1] and of habitation since then. The Romans occupied Portland, reputedly calling it Vindelis.[2][3]

Although the beginning of the Viking Age in England is dated to their raid in 793,[4][5] when they destroyed the abbey on Lindisfarne, their first documented landing occurred in Portland four years earlier, in 789, as recorded in the Anglo-Saxon Chronicle.[verification needed][6][7][8] Three lost Viking ships from Hordaland (the district around Hardanger fjord in west Norway) landed at Portland Bill. The king's reeve tried to collect taxes from them, but they killed him and sailed on.[9]

A castle on the site of the present Rufus Castle, standing over Church Ope Cove, may have been built for William II of England (also known as William Rufus) soon after the conquest of England by his father William the Conqueror. None of that castle remains; the existing castle probably dates from the 15th century.

 Portland Castle was built to defend Portland in the 16th century.

In 1539 King Henry VIII ordered the construction of Portland Castle for defence against attacks by the French; the castle cost £4,964[10] (equivalent to £3.55 million in 2024[11]). It is one of the best preserved castles from this period, and is opened to the public by the custodians English Heritage.[12]

In the 17th century, chief architect and Surveyor-General to James I, Inigo Jones, surveyed the area and introduced the local Portland stone to London, using it in his Banqueting House, Whitehall, and for repairs on St Paul's Cathedral.[13] His successor, Sir Christopher Wren, an architect and the Member of Parliament for nearby Weymouth, used six million tons of white Portland limestone to rebuild destroyed parts of the capital after the Great Fire of London of 1666. Well-known buildings in the capital, including St Paul's Cathedral[14] and the eastern front of Buckingham Palace feature the stone.[15] After the First World War, a quarry was opened by The Crown Estate to provide stone for the Cenotaph in Whitehall and half a million gravestones for war cemeteries,[3] and after the Second World War hundreds of thousands of gravestones were hewn for soldiers who had fallen on the Western Front.[3] Portland cement has nothing to do with Portland; it was so named due to its similar colour to Portland stone when mixed with lime and sand.[16]

 A map of the Isle of Portland from 1937, showing the railway to Easton

There have been railways in Portland since the early 19th century. The Merchant's Railway was the earliest—it opened in 1826 (one year after the Stockton and Darlington railway) and ran from the quarries at the north of Tophill to a pier at Castletown, from where the Portland stone was shipped around the country.[17][18] The Weymouth and Portland Railway was laid in 1865, and ran from a station in Melcombe Regis, across the Fleet and along the low isthmus behind Chesil Beach to a station at Victoria Square in Chiswell.[19] At the end of the 19th century the line was extended to the top of the island as the Easton and Church Ope Railway, running through Castletown and ascending the cliffs at East Weares, to loop back north to a station in Easton.[17] The line closed to passengers in 1952, and the final goods train (and two passenger 'specials') ran in April 1965.[19]

The Royal National Institution for the Preservation of Life from Shipwreck stationed a lifeboat at Portland in 1826, which was withdrawn in 1851.[20] Coastal flooding has affected Portland's residents and transport for centuries—the only way off the island by land is along the causeway in the lee of Chesil Beach. At times of extreme floods (about every 10 years) this road link is cut by floods. The low-lying village of Chiswell used to flood on average every 5 years. Chesil Beach occasionally faces severe storms and massive waves, which have a fetch across the Atlantic Ocean.[21] Following two severe flood events in the 1970s, Weymouth and Portland Borough Council and Wessex Water decided to investigate the structure of the beach, and coastal management schemes that could be built to protect Chiswell and the beach road. In the 1980s it was agreed that a scheme to provide storm protection with a 20% annual exceedance probability to reduce flood depth and duration in more severe storms.[21] Hard engineering techniques were employed in the scheme, including a gabion running 550 metres (600 yd)[22] to the north of Chiswell, an extended sea wall in Chesil Cove, and a culvert running from inside the beach, underneath the beach road and into Portland Harbour, to divert flood water away from low-lying areas.[21]

 Portland Harbour was home to the Royal Navy. Their former barracks are in the foreground.

At the start of the First World War, HMS Hood was sunk in the passage between the southern breakwaters to protect the harbour from torpedo and submarine attack.[23] Portland Harbour was formed (1848–1905) by the construction of breakwaters, but before that the natural anchorage had hosted ships of the Royal Navy for more than 500 years. It was "the home of the Asdics,"[24] a centre for Admiralty research into asdic submarine detection and underwater weapons from 1917 to 1998; the shore base HMS Serepta was renamed HMS Osprey in 1927.[25] During the Second World War Portland was the target of 48 air raids and a total of 532 bombs, although most warships had moved north as Portland was within enemy striking range across the Channel.[26] Mulberry Harbour Phoenix Units can be seen at Black Barge beach, near Portland Castle. Portland was a major embarkation point for Allied forces on D-Day in 1944. Early helicopters were stationed at Portland in 1946–1948, and in 1959 a shallow tidal flat, The Mere, was infilled, and sports fields taken to form a heliport. The station was formally commissioned as HMS Osprey, which then became the largest and busiest military helicopter station in Europe. The base was gradually improved with additional landing areas and one of England's shortest runways, at 229 metres (751 ft).[25]

The naval base closed after the end of the Cold War in 1995, and the Royal Naval Air Station closed in 1999, although the runway remained in use for Her Majesty's Coastguard Search and Rescue flights as MRCC Portland[25] until 2014.[27] MRCC Portland's area of responsibility extended midway across the English Channel, and from Start Point in Devon to the Dorset/Hampshire border, covering an area of around 10,400 square kilometres (4,000 sq mi).[28] The 12 Search and Rescue teams in the Portland area dealt with almost 1000 incidents in 2005.[29] Portland lends its name to one of the BBC's Shipping Forecast regions.

There are still two prisons on Portland: HMP The Verne, which until 1949 was a Victorian military fortress, and a Young Offenders' Institution (HMYOI) on the Grove clifftop.[30] This was the original prison (HM Prison Portland) built for convicts who quarried stone for the Portland Breakwaters from 1848. For a few years until 2005 Britain's only prison ship, HMP The Weare, was berthed in the harbour.[31]

 Weymouth and Portland shown in Dorset