Boundaries , the historic boundary between Gloucestershire and Somerset, and also
Mercia and
Wessex; Somerset is to the left The boundaries of Somerset are largely unaltered from medieval times. The main change has been in the north, where the
River Avon formed the border with Gloucestershire, except that the
hundred of
Bath Forum, which straddles the Avon, formed part of Somerset. Bristol began as a town on the Gloucestershire side of the Avon, but as it grew, it extended across the river into Somerset. In 1373
Edward III proclaimed "that the town of Bristol with its suburbs and precincts shall henceforth be separate from the counties of Gloucester and Somerset ... and that it should be a
county by itself". The present-day northern border of Somerset (adjoining the counties of Bristol and Gloucestershire) runs along the southern bank of the Avon from the Bristol Channel, then follows around the southern edge of the Bristol built-up area, before continuing upstream along the Avon and then diverges from the river to include Bath and its historic hinterland to the north of the Avon, before meeting Wiltshire at the
Three Shire Stones on the
Fosse Way at
Batheaston.
Cities and towns Somerton took over from
Ilchester as the
county town in the late thirteenth century, but it declined in importance and the status of county town transferred to
Taunton about 1366. The county has two
cities,
Bath and
Wells, and
30 towns (including the county town of Taunton, which has no town council but instead is the chief settlement of the county's only extant
borough). The largest urban areas in terms of population are Bath,
Weston-super-Mare, Taunton,
Yeovil and
Bridgwater. Many settlements developed because of their strategic importance in relation to geographical features, such as river crossings or valleys in ranges of hills. Examples include
Axbridge on the
River Axe,
Castle Cary on the
River Cary,
North Petherton on the
River Parrett, and
Ilminster, where there was a crossing point on the
River Isle.
Midsomer Norton lies on the
River Somer; while the
Wellow Brook and the
Fosse Way Roman road run through Radstock.
Chard is the most southerly town in Somerset and one of the highest, though at an altitude of
Wiveliscombe is the highest town in the county.
Green belt The county contains several-miles-wide sections of the Avon
green belt area, which is primarily in place to prevent
urban sprawl from the
Bristol and Bath built up areas encroaching into the rural areas of North Somerset, Bath and North East Somerset, and Mendip districts in the county, as well as maintaining surrounding countryside. It stretches from the coastline between the towns of
Portishead and
Clevedon, extending eastwards past
Nailsea, around the Bristol conurbation, and through to the city of Bath. The green belt border intersects with the Mendip Hills Area of Outstanding Natural Beauty (AONB) along its south boundary, and meets the Cotswolds AONB by its eastern extent along the Wiltshire county border, creating an extended area protected from inappropriate development.
Geology Much of the landscape of Somerset falls into types determined by the underlying geology. These landscapes are the limestone
karst and
lias of the north, the clay
vales and
wetlands of the centre, the
oolites of the east and south, and the
Devonian sandstone of the west. in an artificial channel draining farmland near
Glastonbury To the north-east of the Somerset Levels, the Mendip Hills are moderately high
limestone hills. The central and western Mendip Hills were designated an
Area of Outstanding Natural Beauty in 1972 and cover . The main
habitat on these hills is
calcareous grassland, with some
arable agriculture. To the south-west of the Somerset Levels are the
Quantock Hills which was England's first Area of Outstanding Natural Beauty designated in 1956 which is covered in heathland, oak woodlands, ancient parklands with plantations of conifer and covers 99 square kilometres. The Somerset Coalfield is part of a larger coalfield which stretches into
Gloucestershire. To the north of the Mendip hills is the
Chew Valley and to the south, on the
clay substrate, are broad valleys which support dairy farming and drain into the Somerset Levels.
Caves and rivers There is an extensive network of
caves, including Wookey Hole, underground rivers, and
gorges, including the Cheddar Gorge and
Ebbor Gorge. The county has many rivers, including the Axe,
Brue, Cary, Parrett,
Sheppey,
Tone and
Yeo. These both feed and drain the flat levels and moors of mid and west Somerset. In the north of the county the
River Chew flows into the
Bristol Avon. The Parrett is tidal almost to
Langport, where there is evidence of two Roman wharfs. At the same site during the reign of
King Charles I, river tolls were levied on boats to pay for the maintenance of the bridge. and broadly corresponds to the administrative district of
Sedgemoor but also includes the south west of
Mendip district. Approximately 70% of the area is grassland and 30% is arable. The
North Somerset Levels basin, north of the Mendips, covers a smaller geographical area than the Somerset Levels, and forms a coastal area around
Avonmouth. It too was reclaimed by draining. It is mirrored, across the
Severn Estuary, in Wales, by a similar low-lying area: the
Caldicot and Wentloog Levels. The highest point in Somerset is
Dunkery Beacon on Exmoor, with a maximum elevation of . Over 100 sites in Somerset have been designated as
Sites of Special Scientific Interest.
Coastline from Steep Holm The coastline of the
Bristol Channel and Severn Estuary forms part of the northern border of Somerset. The Bristol Channel has the second largest
tidal range in the world. At
Burnham-on-Sea, for example, the tidal range of a spring tide is more than . Proposals for the construction of a
Severn Barrage aim to harness this energy. The island of
Steep Holm in the Bristol Channel is within the ceremonial county and is now administered by North Somerset Council. The main coastal towns are, from the west to the north-east,
Minehead, Watchet, Burnham-on-Sea, Weston-super-Mare,
Clevedon, and
Portishead. The coastal area between Minehead and the eastern extreme of the administrative county's coastline at
Brean Down is known as
Bridgwater Bay, and is a
National Nature Reserve. North of that, the coast forms
Weston Bay and
Sand Bay whose northern tip,
Sand Point, marks the lower limit of the Severn Estuary. In the mid and north of the county the coastline is low as the level wetlands of the levels meet the sea. In the west, the coastline is high and dramatic where the
plateau of Exmoor meets the sea, with high cliffs and waterfalls.
Climate Along with the rest of
South West England, Somerset has a temperate climate which is generally wetter and milder than the rest of the country. The annual mean temperature is approximately .
Seasonal temperature variation is less extreme than most of the United Kingdom because of the adjacent sea temperatures. The summer months of July and August are the warmest with mean daily maxima of approximately . In winter mean minimum temperatures of or are common. In the summer the
Azores high pressure affects the south-west of England, but
convective cloud sometimes forms inland, reducing the number of hours of sunshine. Annual sunshine rates are slightly less than the regional average of 1,600 hours. In December 1998, there were 20 days without sun recorded at Yeovilton. Most of the rainfall in the south-west is caused by
Atlantic depressions or by convection. Most of the rainfall in autumn and winter is caused by the Atlantic depressions, which are when they are most active. In summer, a large proportion of the rainfall is caused by the sun heating the ground, leading to convection and showers and thunderstorms. Average rainfall is around . About 8–15 days of snowfall is typical. November to March have the highest mean wind speeds, and June to August have the lightest winds. The predominant wind direction is from the south-west. ==Demographics==