The Isle of Portland is not really an island, however it is only joined to the mainland by a narrow strip of land and the Chesil Beach. The mass of land that juts out into the channel is formed from a block of limestone 4.5 miles long by 1.75 miles wide, it rises from near sea level in the south to over 400 ft high in the north.

Portland has been inhabited since early times and traces of occupation have been dated back 7,000 years. The Romans knew it as ‘Vindilis’ and Thomas Hardy wrote about it as ‘The Isle of Slingers’ due to the fact that Portlanders used to throw stones to keep Kimberlins (strangers) away, it is a Royal Manor and many of the quarries which dot the landscape are owned by the crown. The breakwater which forms one of the largest harbors in the world, some 2130 acres, was started in 1849. Prince Albert laid the foundation stone on the 25 July and Albert Edward, Prince of Wales laid the last stone on 18 August 1872. The twenty three years of construction had cost the lives of twenty two men, most of the construction was carried out by convicts. These convicts had hewn 5,731,376 tons of stone to form the breakwaters and the cost in 1871 was £1,167,852.

Portland Castle at Castletown was built in 1539 following attacks by the French, its partner at Sandsfoot, Wyke Regis is now but a ruin due to sea erosion of the sandstone cliffs. The Castle is built of Ashlar stone, the finest Portland Stone available, and cost £4,964 at its completion around 1540. It is one of the best preserved of Henry Vlll’s castles and is of interest as it shows the transition from medieval to more modern methods of fortification. These days the Verne is a prison, but it was originally constructed as a citadel for the army and held 700 men, though in time of war it could accommodate over 2000. It was heavily fortified and was heavily armed with 30 ton guns.

To the east of the island is Portland Harbour, sheltered by breakwaters constructed in the last century by prisoners from the Verne Prison on Portland. From 1872 to 1985 this was one of the United Kingdom's main Naval bases, which is now closed as a result of the end of the Cold War and 'down-sizing' of military forces. One part of the Navy presence remains until 1998 - a Royal Naval Air Station which trains helicopter pilots, and is the largest purpose built Hele-Port in the world. A Search and Rescue helicopter service runs from here.

 The coastline of Portland is very dangerous to mariners, especially at night and in fog, and the Southern tip of the island is dominated by a lighthouse, which became automatic in 1996, and there are plans to turn it into a tourist attraction. Nearby is a smaller, older lighthouse, now used as an observation tower by ornithologists.

Portland owes its international importance to this stone. Quarrying was for many years the main industry on the island, and the use of the stone extends from St Paul's Cathedral in London to the United Nation Headquarters in New York.

 Indigo Jones had used Portland stone before the Civil War, and Sir Christopher Wren, Weymouth’s MP, used it to rebuild London after the Great Fire of 1666. St Paul’s Cathedral and some fifty other churches and other buildings were built with the famous white limestone. Over six million tons were used in the rebuilding, the stone was loaded onto barges from piers on the east side of the island then transported along the coast and up the River Thames to the building sites.

In 1972 approximately 600 tons of stone were quarried for the restoration and repair of St Paul’s Cathedral. Included in the delivery was a block originally selected and marked for Sir Christopher Wren, 300 years earlier.

The stone was also used for the Whitehall Cenotaph, the national memorial for the dead of the Great War. A special quarry was opened at Wakeham for the carefully selected stone, and the order from the Commonwealth War Graves was for half a million headstones, all were shaped, carved with names and badges and shipped from Portland to the Western Front. Over 800,000 gravestones were also produced in the 1950’s for the nation’s war dead of the Second World War.