The Chiltern Hills or the Chilterns () are a chalk escarpment in southern England to the north-west of London, covering across Oxfordshire, Buckinghamshire, Hertfordshire and Bedfordshire. The hills stretch from Goring-on-Thames in the south-west to Hitchin in the north-east, and are at their widest.
In 1964, - almost half of the Chiltern Hills - were designated by the Countryside Commission as an Area of Outstanding Natural Beauty (AONB) under the powers established by the National Parks and Access to the Countryside Act 1949.
The north-west boundary of the Chilterns is clearly defined by the escarpment. The dip slope is by definition more gradual and merges with the landscape to the south-east. The south-west endpoint is the River Thames. The hills decline slowly in prominence in north-east Bedfordshire.The Changing Landscape of the Chilterns Chilterns AoNB, Accessed 19 February 2012Chiltern Society, The Chilterns .
Toponymy The toponym, Chiltern, is believed to be Brittonic in origin. According to Eilert Ekwall, Chiltern is possibly related to the broader ethnic name Celt (Celtæ in early Celtic languages); the root celto- "high" (and suffix -erno-) could provide the origin of Chiltern. Ekwall cites the forms Cilternsætna (Birch's Cartularium Saxonicum; 297); Cilternes efes (Kemble's Codex diplomaticus aevi Saxonici; 715) and Ciltern (Anglo-Saxon Chronicle; text E)
History
During the Iron Age, the Chiltern ridge provided a relatively safe and easily navigable route across southern Britain.
Before the 18th century, the population lived dispersed across the largely rural landscape of the Chilterns in remote villages, hamlets, farmsteads, and market towns along the main turnpike routes which coursed through the navigable valleys. The development of canals in the 18th century and railways in the 19th century encouraged settlement and the growth of High Wycombe, Tring and Luton. Significant housing and industrial development took place throughout the 20th century.
In 1965, almost half of the Chiltern Hills was designated as an AONB.
Geology
The chalk escarpment of the Chiltern Hills overlooks the Vale of Aylesbury and roughly coincides with the southernmost extent of the ice sheet during the Anglian glacial maximum. The Chilterns are part of a system of chalk downlands throughout eastern and southern England, consisting of rocks of the Chalk Group, formed between 95 and 65 million years ago; it also includes Salisbury Plain, Cranborne Chase, the Isle of Wight and the South Downs in the south. In the north, the chalk formations continue north-eastwards across Hertfordshire, Norfolk and the Lincolnshire Wolds, finally ending as the Yorkshire Wolds in a prominent escarpment, south of the Vale of Pickering.
The beds of the Chalk Group were deposited over the buried north-western margin of the Anglo-Brabant Massif during the Late Cretaceous. During this time sources for siliciclastic sediment had been eliminated owing to the exceptionally high sea level. The formation is thinner through the Chiltern Hills than the chalk strata to the north and south and deposition was tectonically controlled, with the Lilley Bottom structure playing a significant role at times.Rawson, P.F. 2006. Cretaceous: sea levels peak as the North Atlantic opens. In: P.J. Brenchley and P.F. Rawson (Eds) The Geology of England and Wales, p.365-393. The Geological Society The base of the Chalk Group, like the underlying Gault Clay and Upper Greensand, is diachronous.Anderson, R., P.H. Bridges, M.R. Leeder and B.W. Sellwood (Eds) 1979. A Dynamic Stratigraphy of the British Isles: A Study in Crustal Evolution. p. 241. George Allen and Unwin, London.
During the late stages of the Alpine Orogeny, as the African Plate collided with Eurasian Plate, Mesozoic extensional structures, such as the Weald Basin of southern England, underwent structural inversion. This phase of deformation tilted the chalk strata to the south-east in the area of the Chiltern Hills. The gently dipping beds of rock were eroded, forming an escarpment.
The chalk strata are frequently interspersed with layers of flint nodules, which apparently replaced chalk and infilled pore spaces early in the diagenetic history. Flint has been mined for millennia from the Chiltern Hills. It was first extracted for fabrication into flint axes in the Neolithic period, then for knapping into flintlocks. Nodules are to be seen everywhere in the older houses as a construction material for walls.
Physical characteristics Topography
The highest point is above sea level at Haddington Hill, near Wendover in Buckinghamshire; a stone monument marks the summit. The nearby Ivinghoe Beacon is a more prominent hill, although its altitude is only . It is the starting point of the Icknield Way Path and the Ridgeway long-distance path, which follow the line of the Chilterns for many miles to the west, where they merge with the Wiltshire downs and southern Cotswolds.
To the east of Ivinghoe Beacon are the Dunstable Downs, a steep section of the Chiltern scarp. Near Wendover is Coombe Hill, above sea level. The more gently sloping country – the dip slope – to the south-east of the Chiltern scarp is also generally referred to as part of the Chilterns and contains much beech woodland and many villages.
Landscape and land use Enclosed fields account for almost 66% of the AONB. The next most important, and archetypal, landscape form is woodland, covering 21% of the Chilterns, which is thus one of the most heavily wooded areas in England. Built-up areas (settlements and industry) make up more than 5% of the land area; parks and gardens nearly 4%; open land (commons, heaths and downland) is 2%; and the remaining 2% includes a variety of uses, including communications, military, open land, recreation, utilities and water.
Rivers The Chiltern Hills are almost entirely within the River Thames drainage basin and also drain towards several major Thames tributaries, most notably the Lea, which rises in the eastern Chilterns, the Colne to the south and the Thame to the north and west.
Other rivers arising near the Chilterns include the Mimram, the Ver, the Gade, the Bulbourne, the Chess, the Misbourne and the Wye. These are classified as chalk streams, although the Lea is degraded by water from road drains and sewage works.Nau B.S., Boon C.R., and Knowles J.P., Bedfordshire Wildlife, Castlemead, 1987, , page 71. The Thames flows through a gap between the Berkshire Downs and the Chilterns. Portions around Leighton Buzzard and Hitchin are drained by the Ouzel, the Flit and the Hiz, all of which ultimately flow into the River Great Ouse; the last two via the Ivel.
Transport
Several transport routes pass through the Chilterns in natural or human-made corridors. There are also over of public footpaths, including long-distance trackways such as the Icknield Way and The Ridgeway.DidYouKnow.pdf Chilterns AoNB, Accessed 19 February 2012
The M40 motorway passes through the Chilterns in Buckinghamshire and Oxfordshire sections with a deep cutting through the Stokenchurch Gap. The M1 motorway crosses the Bedfordshire section near Luton. Other major roads include the A41 and the A413.
The Chiltern Main Line, via and ; the London to Aylesbury Line, via ; the West Coast Main Line, via ; and the Midland Main Line all run through the Chiltern Hills. The Great Western Main Line and its branches, such as the Henley and Marlow branch lines, link the southern side of the Chilterns with . The Chinnor and Princes Risborough Railway is a preserved heritage line.
High Speed 2 (HS2) will pass underneath the Chilterns in the Chiltern Tunnel; the longest under construction on the route will be in length. The Conservation Board was opposed to the routing of HS2 through the Chilterns AONB.Chilterns Conservation Board – statement objecting to HS2, Accessed 12 December 2012Chilerns AoNB website – HS2, Accessed 20 February 2012
Bus services are provided by Arriva Shires & Essex and Carousel Buses.
Air corridors from Luton Airport pass over the Chilterns.
Apart from the Thames, there are no navigable rivers. The Grand Union Canal passes through the Chilterns between Berkhamsted and Marsworth, following the course of the Gade and Bulbourne. Also, after crossing a watershed, the Ouzel is partly in the Chilterns.
List of towns and villages Aldbury, Amersham, Apsley, Ashridge, Aston Clinton Barton-le-Clay, Beaconsfield, Bellingdon, Berkhamsted, Bledlow Ridge, Bovingdon, Bradenham, Breachwood Green, Buckland Common Caddington, Chalfont St Giles, Chalfont St Peter, Chartridge, Checkendon, Cheddington, Chesham, Chiltern Green, Chinnor, Cholesbury, Christmas Common, Coleshill Dagnall, Downley, Dunsmore, Dunstable Edlesborough, Ellesborough Fawley, Fingest, Flackwell Heath, Frieth Gerrards Cross, Goring-On-Thames, Great Hampden, Great Kingshill, Great Missenden, Great Offley Halton, Hambleden, Harlington, Hawridge, Hazlemere, Hemel Hempstead, Henley-on-Thames, Hexton, High Wycombe, Hitchin, Holmer Green, Hughenden, Hyde Heath Ibstone, Ivinghoe, Jordans, Kensworth Lacey Green, Lane End, Latimer, Ley Hill, Lilley, Little Chalfont, Little Gaddesden, Little Kingshill, Little Missenden, Luton Markyate, Marlow, Marlow Bottom, Medmenham Naphill, Nettlebed, Nuffield Penn, Pishill, Pitstone, Prestwood, Princes Risborough, Radnage, Redbourn Seer Green, Sharpenhoe, Shiplake, Skirmett, Southend, South Heath, Speen, St Leonards, Stokenchurch, Stoke Poges, Stonor, Streatley (Beds), Studham Thame, The Lee, Tring, Turville, Tylers Green Walter's Ash, Watlington, Wendover, West Wycombe, Whipsnade, Whitwell, Wigginton, Winchmore Hill, Woodcote.
Strip parishes The western edge of the Chilterns is notable for ancient strip parishes; these are elongated parishes with villages in the flatter land below the escarpment, with woodland and summer pastures in the higher land: Bedfordshire: Eaton Bray, Toddington, Totternhoe Berkshire: Caversham, Cookham, Hurley, Maidenhead, Reading, Ruscombe, Sonning, Twyford, Wargrave, Wokingham Buckinghamshire: Aston Clinton, Aylesbury, Bledlow, Bourne End, Buckland, Drayton Beauchamp, Great Kimble, Horsenden, The Lee, Marsworth, Monks Risborough, Pitstone, Princes Risborough, Saunderton, Stoke Mandeville, Weston Turville Hertfordshire: Tring, Wigginton Oxfordshire: Aston Rowant, Checkendon, Chinnor, Didcot, Ipsden, Lewknor, Mongewell, Newnham Murren, Nuffield, Peppard Common, Pyrton, Shirburn, Sonning Common South Stoke, Wallingford, Watlington.
Economic use
The hills have been used for their natural resources for millennia. The chalk has been quarried for the manufacture of cement, and flint for local building material. Beechwoods supplied furniture makers with quality hardwood. The area was once (and still is to a lesser degree) renowned for its chair-making industry, centred on the towns of Chesham and High Wycombe; the nickname of Wycombe Wanderers football club is the "Chairboys".
Water was and remains a scarce resource in the Chilterns. Historically it was drawn from the aquifer via ponds, deep wells, occasional springs or bournes and chalk streams and rivers. The river Chess directly supplies watercress beds. Today the chalk aquifer is exploited via a network of pumping stations to provide a public supply for domestic consumption, agriculture and business uses, both within and well-beyond the Chilterns area. Over-exploitation has possibly led to the disappearance of some streams over long periods.Chess Valley Association, Accessed 4 September 2014
In a region without building stone, local clay provided the raw materials for brick manufacture; timber and flint were also used for construction.