It is bordered by Somerset to the north-west, Wiltshire to the north and the north-east, Hampshire to the east, the Isle of Wight across the Solent to the south-east, the English Channel to the south, and Devon to the west.

The majority of its coastline is part of the Jurassic Coast World Heritage Site due to its geological and palaeontologic significance, and features notable landforms such as Lulworth Cove, the Isle of Portland, Chesil Beach and Durdle Door.

There is evidence of Neolithic, Celtic, and Roman settlement in Dorset, and during the Early Middle Ages the region was settled by the Saxons; the county developed in the 7th century.

The first recorded Viking raid on the British Isles occurred in Dorset during the eighth century, and the Black Death entered England at Melcombe Regis in 1348.

During the Second World War, Dorset was heavily involved in the preparations for the invasion of Normandy, and the large harbours of Portland and Poole were two of the main embarkation points.

[3] The Romans established the settlement in the 1st century and named it Durnovaria which was a Latinised version of a Common Brittonic word possibly meaning "place with fist-sized pebbles".

Exeter and Gloucester) and Dornsæte came into use as the name for the inhabitants of the area from Dorn (a reduced form of Dornwaraceaster) and the Old English word sæte (meaning "people").

[14][15] Bokerley Dyke, a large defensive ditch built by the county's post-Roman inhabitants near the border with modern-day Hampshire, delayed the advance of the Saxons into Dorset for almost 150 years.

[16] It appears to have been re-fortified during this period, with the former Roman Road at Ackling Dyke also being blocked by the Britons, apparently to prevent the West Saxon advance into Dorset.

Over a five-day period in Dorchester, Judge Jeffreys presided over 312 cases: 74 of the accused were executed, 175 were sentenced to penal transportation, and nine were publicly whipped.

[39] Poole became Dorset's busiest port and established prosperous trade links with the fisheries of Newfoundland which supported cloth, rope and net manufacturing industries in the surrounding towns and villages.

The labourers, who are now known as the Tolpuddle Martyrs, were subsequently arrested for administering "unlawful oaths" and sentenced to transportation but they were pardoned following massive protests by the working classes.

[44][45] The Dorsetshire Regiment were the first British unit to face a gas attack during the First World War (1914–1918) and they sustained particularly heavy losses at the Battle of the Somme.

[47][48] During the Second World War (1939–1945) Dorset was heavily involved in the preparations for the invasion of Normandy: beach landing exercises were carried out at Studland and Weymouth and the village of Tyneham was requisitioned for army training.

[51] First popularised as a tourist destination by George III's frequent visits to Weymouth, the county's coastline, seaside resorts and its sparsely populated rural areas attract millions of visitors each year.

[61][62] Blandford Forum, Sherborne, Gillingham, Shaftesbury and Sturminster Newton are historic market towns which serve the farms and villages of the Blackmore Vale in north Dorset.

[63] Beaminster and Bridport are situated in the west of the county; Verwood and the historic Saxon market towns of Wareham and Wimborne Minster are located to the east.

[64] Under construction on the western edge of Dorchester is the experimental new town of Poundbury commissioned and co-designed by Charles III when he was Prince of Wales.

[65] The suburb, which is expected to be fully completed by 2025, was designed to integrate residential and retail buildings and counter the growth of dormitory towns and car-oriented development.

[66] Dorset covers an area of 2,653 square kilometres (1,024 sq mi) and contains considerable variety in its underlying geology, which is partly responsible for the diversity of landscape.

[79] South-east Dorset, including the lower Frome valley and around Poole and Bournemouth, comprises younger Eocene deposits,[74] mainly sands and clays of poor agricultural quality.

[90] The harbour, and the chalk and limestone hills of the Isle of Purbeck to the south, lie atop Western Europe's largest onshore oil field.

[91] The field, operated by Perenco from Wytch Farm, has the world's oldest continuously pumping well at Kimmeridge which has been producing oil since the early 1960s.

[91][92] Dorset's diverse geography ensures it has an assortment of rivers, although a moderate annual rainfall coupled with rolling hills, means most are typically lowland in nature.

[99] The Dorset section has yielded important fossils, including Jurassic trees and the first complete Ichthyosaur, discovered near Lyme Regis in 1811 by Mary Anning.

Dorset became a two-tier non-metropolitan county after a reorganisation of local government in 1974 and its border was extended eastwards to incorporate the former Hampshire towns of Bournemouth and Christchurch.

[154] Dorset's three ports, Poole, Weymouth and Portland, and the smaller harbours of Christchurch, Swanage, Lyme Regis, Wareham and West Bay generate a substantial amount of international trade and tourism.

[156] When the waters around Weymouth and Portland were chosen for the sailing events in the 2012 Summer Olympic Games, the area underwent an increased investment in infrastructure and a growth in the marine leisure sector.

[162] Numbers of domestic and foreign tourists have fluctuated in recent years due to various factors including security and economic downturn, a trend reflected throughout the UK.

[174][175] Grade I listed buildings include: Portland Castle, a coastal fort commissioned by Henry VIII;[176] a castle with more than a 1,000 years of history at Corfe;[177] a Roman ruin described by Historic England as the "only Roman town house visible in Britain";[178] Athelhampton, a Tudor manor house;[179] Forde Abbey, a stately home and former Cistercian monastery;[180] Christchurch Priory, the longest church in England;[181] and St Edwold's church, one of the smallest.