[2] The southern tip, Portland Bill, lies 8 kilometres (5 mi) south of the resort of Weymouth, forming the southernmost point of the county of Dorset, England.

Portland stone, a limestone famous for its use in British and world architecture, including St Paul's Cathedral and the United Nations Headquarters, continues to be quarried here.

[4][5] Although the beginning of the Viking Age in England is dated to their raid in 793,[6][7] 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][8][9][10] Three lost Viking ships from Hordaland (the district around Hardanger fjord in west Norway) landed at Portland Bill.

[14] 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 Old St Paul's Cathedral.

[15] 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[16] and the eastern front of Buckingham Palace feature the stone.

[22] 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.

[23] Hard engineering techniques were employed in the scheme, including a gabion running 550 metres (600 yd)[24] 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.

[23] 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.

[25] 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.

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.

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.

[40] In 2019, the borough of Weymouth and Portland was abolished when Dorset moved to a unitary authority structure of local government.

Portland is unusual as it is connected to the mainland at Abbotsbury by Chesil Beach, a tombolo which runs 29 kilometres (18 mi) north-west to West Bay.

[49] Many old buildings are built out of Portland Stone; several parts have been designated Conservation Areas to preserve the unique character the older settlements which date back hundreds of years.

[57] Due to its isolated coastal location, the Isle of Portland has an extensive range of flora and fauna; the coastline and disused quarries are designated as Sites of Special Scientific Interest.

[45][58] The Isle of Portland SSSI encompasses 352 hectares (870 acres), and includes 17 monitored features ranging from Jurassic fossils, calcareous grassland, rock sea-lavender and nationally scarce butterflies.

[59] Sea and migratory birds occupy the cliffs in different seasons, sometimes these include rare species which draw ornithologists from around the country.

[60] Ten British Primitive goats were introduced to the East Weares part of the island to control scrub in 2007.

However, due to the island's proximity to the sea, summers are cooler than the national average, with temperatures rarely climbing to the extremes seen in in-land areas further north.

[65] As a result of its coastal extremity and mild winter minimum temperatures, Portland is suitable for plants with the Royal Horticultural Society's hardiness rating H2.

[81] Trains run from Weymouth to London, Southampton, Bristol and Gloucester but ferries no longer transport passengers to the French port of St Malo and the Channel Islands of Guernsey and Jersey.

[89] In 2005, the WPNSA was selected to host sailing events at the 2012 Olympic Games—mainly because the academy had recently been built, so no new venue would have to be provided.

[90] However, as part of the South West of England Regional Development Agency's plans to redevelop Osprey Quay, a new 600-berth marina and an extension with more on-site facilities were built.

Chesil Beach and Portland Harbour are used regularly for angling, scuba diving to shipwrecks, snorkelling, canoeing, and swimming.

They would see rabbits emerging from their burrows immediately before a rock fall and blame them for increasing the risk of dangerous, sometimes deadly, landslides.

[102] As of 2006, older Portland residents were said to be 'offended' (sometimes for the benefit of tourists) by the mention of rabbits;[103] this superstition came to national attention in October 2005 when a special batch of advertisement posters were made for the Wallace and Gromit film, The Curse of the Were-Rabbit.

[107][108] In Museums Without Walls, Jonathan Meades declares that "Portland is a bulky chunk of geological, social, topographical and demographic weirdness.

"[109] In The Warlord Chronicles (1995–97), Bernard Cornwell makes Portland the Isle of the Dead, a place of internal exile, where the causeway was guarded to keep the 'dead' (people suffering insanity) from crossing the Fleet and returning to the mainland.