Sussex is a historic county and cultural region in the south of England corresponding roughly in area to the ancient Kingdom of Sussex. It is bounded on the north by Surrey, north-east by Kent, south by the English Channel, and west by Hampshire, and is divided for local government into West Sussex and East Sussex and the city of Brighton and Hove. The city of Brighton & Hove was created a unitary authority in 1997, and was granted City status in 2000. Until then Chichester had been Sussex's only city. By convention, Chichester is Sussex's capital city and Lewes is Sussex's county town.

Sussex encompasses approximately . It is long and is between wide. For comparison, Sussex is slightly larger than the neighbouring county of Kent or Cornwall or the Indian state of Goa and is 50 per cent larger than Luxembourg. Sussex has a population of about 1.6 million,Combined population of local authority areas of Brighton and Hove (273,400), East Sussex, (527,200) and West Sussex (808,900) about the same as Goa or the US state of Idaho and about three times the population of Cornwall.

Sussex has three main geographic sub-regions, each orientated approximately east to west. In the south-west of the county lies the fertile and densely populated coastal plain. North of this lie the rolling chalk hills of the South Downs, beyond which lies the well-wooded Sussex Weald.

Climate The coastal resorts of Sussex and neighbouring Hampshire are the sunniest places in the United Kingdom. The coast has consistently more sunshine than the inland areas: sea breezes, blowing off the sea, tend to clear any cloud from the coast. Most of Sussex lies in Hardiness zone 8; the exception is the coastal plain west of Brighton which lies in the milder zone 9.

Rainfall is below average with the heaviest precipitation on the South Downs with of rainfall per year. The close proximity of Sussex to the Continent of Europe, results in cold spells in winter and hot, humid weather in summer.

The climate of the coastal districts is strongly influenced by the sea, which, because of its tendency to warm up slower than land, can result in cooler temperatures than inland in the summer. In the autumn months, the coast sometimes has higher temperatures. Rainfall during the summer months is mainly from thunderstorms and thundery showers; from January to March the heavier rainfall is due to prevailing south-westerly frontal systems.

In winter the east winds can be as cold as further inland. Selsey is known as a tornado hotspot, with small tornadoes hitting the town in 1986, 1998 and 2000, with the 1998 tornado causing an estimated £10 million of damage to 1000 buildings.

Geology

Sussex's geology typically runs in bands running east–west. Running across the south of the county, from Hampshire to chalk cliffs of Beachy Head lies the chalk ridge of the South Downs. The South Downs form the southern rim of the Wealden anticline, a large and eroded dome of rocks, largely of Cretaceous age (140-65 million years old) which has had a significant influence on the development of the diverse topography of the county. Small exposures of rocks of Jurassic age (195-140 million years old) occur on the main axis of the Weald anticline and rocks of Tertiary age (65-2 million years old) are exposed along the coast in West Sussex. During the ice ages no glaciers reached Sussex, but the county was under the influence of very cold tundra-like conditions at the edge of the ice sheets. Processes of erosion and deposition during this period have contributed significantly to the formation of the present landscape.

With the exception of the youngest part of the Chalk, Sussex provides an almost complete sequence of Cretaceous rocks. They dip to the south with the consequence that increasingly younger rocks are exposed the further south you go. From the summit of the Downs the hilly country observed on the northern side is occupied mainly by the Hastings Beds and the Weald Clay; at the foot of the escarpment lie the Gault and Upper Greensand, while between these formations and the Wealden rocks there is an elevated ridge of ground formed by the Lower Greensand.

Between the South Downs and the English Channel is the South Coast Plain, also known as the Sussex-Hampshire Plain, part of the Hampshire-Dieppe basin, and it owes its level character to the action of marine planation. The plain is occupied partly by chalk and partly by Tertiary rocks, both much obscured by more recent deposits. The Eocene strata lying south of the Downs and west of Brighton - with the exception of some outliers of Reading Beds near Seaford - include the Woolwich and Reading Beds, London Clay (with hard "Bognor Rock"), the Bagshot and the Bracklesham Beds, which contain many fossils. Superficial deposits cover much of the coastal plain; these include glacial deposits with large boulders, raised beaches, brick earth and gravels, marine and estuarine, and the interesting Lower chalk or Coombe rock, formerly known as Elephant Beds, a coarse rubble of chalk waste formed late in the Glacial period, well exposed in the cliff at Black Rock east of Brighton, where it rests on a raised beach.

The southern side of the South Downs are deeply notched by dry valleys or coombes, which frequently end in cirques near the northern escarpment. Devil's Dyke is the most famous and remarkable of all the chalk dry valleys and is frequently cited as the type example. It is the largest single coombe anywhere in the chalk karst of Britain.

At one time there is no doubt that the Chalk, Greensand and Gault of the Wealden anticline covered the entire area in the form of an uplifted dome, but denudation has removed the Chalk and most of the other formations as far as the North Downs, thereby exposing the underlying Wealden Beds. The oldest rocks thus brought to light along the crest of the anticline are the Purbeck Beds, small patches of shale and limestone, with some important beds of gypsum, which lie north-west of Battle. A deep boring (1905 ft.) at Netherfield, passed through Portlandian Beds and Kimmeridge Clay into Oxford Clay, but these do not appear anywhere at the surface. Above the Purbeck Beds, and covering all the north-eastern portion, of the county from the coast at Bexhill and Rye to Horsham, are sands and clays of the Lower Wealden or Hastings Beds. This includes the following local subdivisions, in ascending order; the Fairlight Clay, Ashdown Sand, Wadhurst Clay, Lower Tunbridge Wells Sand, Grinstead Clay and Upper Tunbridge Wells Sand (with Tilgate stone at the top and Cuckfield Clay at the base). The Weald Clay occupies a belt of lower ground on the south and west of the Hastings Sands, it consists of blue and mottled clays with thin sand layers and beds of hard limestone, the "Sussex marble" with the shells of Viviparus. Horsham Stone is another local hard bed. Near Tilgate the remains of Iguanodon were found by Sussex geologist Gideon Mantell in this formation.

Bordering the outcrop of the Weald Clay is the Lower Greensand Group; it appears a little north of Eastbourne and passes thence through Ringmer, Storrington, Pulborough, Petworth, Midhurst and Linchmere. It contains the following divisions in ascending order - the Atherfield Clay, Hythe Beds (sandy limestone, sandstone and chert), Sandgate Beds and Folkestone Beds. The natural gas of Heathfield comes from the Lower Wealden and Purbeck Beds. Wadhurst Clay was formerly an important source of iron ore.

Natural resources Sussex's natural resources have been used for thousands of years. The South Downs includes some of Britain's earliest mines, including Church Hill, Findon which dates from around 4200BC. while the Sussex Weald was historically the centre of England's iron industry, using iron ore in the form of siderite. The Wealden iron industry was established before the Roman invasion and was superseded in the 18th century by coal areas of Wales and northern England. There remains a long-established deep-mining operation centred on the High Weald village of Brightling, the country's largest resource of calcium sulphate or gypsum. Used primarily to make plaster, plasterboard and cement, gypsum has been excavated in the area since the 1880s.

In the 21st century, there has been oil drilling at Singleton, in the South Downs north of Chichester as well as Baxters Copse and Storrington in the Low Weald. With some controversy locally, hydraulic fracturing of shale gas has been proposed to be taken from the Low Weald near Balcombe close to the Brighton Main Line railway. A proposed wind farm off just 10 miles off the Sussex coast called Rampion, named by E.ON after the county flower for Sussex, would according to E.ON, deliver 450MW of electricity.

Major towns and cities Sussex's population is dominated by the Brighton/Worthing/Littlehampton conurbation which with a population of over 460,000 is home to almost 1 in 3 of Sussex's population. According to the ONS urban area populations for continuous built-up areas, these are the 5 largest conurbations (population figures from the 2001 census): RankUrban AreaPopulation (2001 Census)KS01 Usual resident population, Key Statistics for Settlements and Localities Scotland General Register Office for ScotlandLocalitiesComments1Brighton/Worthing/Littlehampton461,18110Sometimes referred to as two primary urban areas – Brighton Urban Area and Worthing Urban Area2Crawley180,1776 Includes approx. 74,000 people living in Surrey3Hastings/Bexhill126,38624Eastbourne106,56215Bognor Regis62,1411

The largest towns and cities in Sussex are as follows: Brighton and Hove Crawley Worthing Eastbourne Hastings Horsham Bexhill

Physical geography Extreme points Northernmost point – Junction of A23 London Road and Povey Cross Road, north of Gatwick Airport, Crawley, West Sussex at Southernmost point – Selsey Bill, West Sussex at Westernmost point – Stansted Park, Stoughton, West Sussex at Easternmost point – Denge Marsh, near Camber Sands, East Sussex at

Natural areas and hills Natural England has identified the following seven national character areas in Sussex:

South Coast Plain South Downs Wealden Greensand Low Weald High Weald Pevensey Levels Romney Marshes

At 280m Blackdown is the highest point in Sussex, or county top. Ditchling Beacon (248m) is the highest point in East Sussex. Sussex's second highest point and the highest point in Sussex on the South Downs is Crown Tegleaze at 255m tall. Sussex contains seven Marilyns, that is peaks that have 150m or more of relative height.: Blackdown, Ditchling Beacon, Crowborough Beacon (242m), Chanctonbury Hill (240m), Firle Beacon (217m), Wilmington Hill (214m) and Cliffe Hill (164m).

Coastal plain This is a fertile narrow belt from Chichester to Brighton. Once noted for market gardening, it is now heavily built up into a sprawling coastal conurbation. The beaches along the coast vary from sandy to shingle: that factor, together with the mild climate of the coast, sheltered by the hills from north and east winds, has resulted in the growth of numerous resort towns, of which the most popular are (east to west) Brighton, Shoreham-by-Sea, Worthing, Littlehampton and Bognor Regis.

South Downs

The South Downs start from a point near Petersfield in Hampshire. On entering Sussex, their summit is about from the sea. They run east for some , gradually approaching the coast, and terminating in the bold promontory of Beachy Head near Eastbourne. Their average height is about though Ditchling Beacon is (the third highest summit) and many other summits exceed .

The Weald