Chiltern Hills
Highest point
PeakHaddington Hill
Elevation267 m (876 ft)
Length74 km (46 mi)
Width18 km (11 mi)
Area1,700 km2 (660 sq mi)
Map of England with a green area representing the location of the Chiltern Hills AONB
Location of the Chiltern Hills AONB in England
LocationSoutheast of England
East of England
CountryUnited Kingdom
Range coordinates51°40′N 0°55′W / 51.667°N 0.917°W / 51.667; -0.917
Type of rockchalk downland

The Chiltern Hills are a chalk escarpment in southern England,[1] northwest of London, covering 660 square miles (1,700 km2) across Oxfordshire, Buckinghamshire, Hertfordshire, and Bedfordshire, stretching 45 miles (72 km) from Goring-on-Thames in the southwest to Hitchin in the northeast. The hills are 12 miles (19 km) at their widest.

In 1965, almost half of the Chiltern Hills was designated as an Area of Outstanding Natural Beauty (AONB). The northwest boundary is clearly defined by the escarpment. The dip slope is by definition more gradual, and merges with the landscape to the southeast.[2] The southwest endpoint is the River Thames. The hills decline slowly in prominence in northeast Bedfordshire.[3][4]


Chalk visible in ploughed soil at the foot of the Chiltern Hill escarpment near Shirburn on the Buckinghamshire/Oxfordshire border

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.[citation needed] The Chiltern Hills are part of a system of chalk downlands throughout eastern and southern England, formed between 65 and 95 million years ago,[3] comprising rocks of the Chalk Group; this also includes Salisbury Plain, Cranborne Chase, the Isle of Wight and the South Downs in the south. In the north, the chalk formations continue northeastwards 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 northwestern margin of the Anglo-Brabant Massif during the Late Cretaceous.[5] During this time, sources for siliciclastic sediment had been eliminated due to the exceptionally high sea level.[6] 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.[5] The Chalk Group, like the underlying Gault Clay and Upper Greensand, is diachronous.[6]

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.[5] This phase of deformation tilted the chalk strata to the southeast 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.[7] They were 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


Viewed from The Ridgeway: eastern trailhead on Ivinghoe Beacon

The highest point is at 267 m (876 ft.) 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 249 m (817 ft.).[8] It is the starting point of the Icknield Way Path and the Ridgeway long-distance path, which follows the line of the Chiltern Hill for many miles to the west, where they merge with the Wiltshire downs and southern Cotswolds. To the east of Ivinghoe Beacon is Dunstable Downs, a steep section of the Chiltern scarp. Near Wendover is Coombe Hill, 260 m (852 ft.) above sea level. The more gently sloping country – the dip slope – to the southeast of the Chiltern scarp is also generally referred to as part of the Chiltern Hills; it contains much beech woodland[1] and many villages.

Further information: Ipsden Heath

Landscape and land use

Enclosed fields account for almost 66% of the "Area of Outstanding Natural Beauty" (AONB) area. The next most important, and archetypal, landscape form is woodland, covering 21% of the Chiltern Hills, which is thus one of the most heavily wooded areas in England. Built-up areas (settlements and industry) make up over 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.[3]


The Chiltern Hills are almost entirely located within the River Thames drainage basin, and also drain towards several major Thames tributaries, most notably the Lea, which rises in the eastern Chiltern Hills, the Colne to the south, and the Thame to the north and west. Other rivers arising near the Chiltern Hills 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 treatment works.[9] The Thames flows through a gap between the Berkshire Downs and the Chiltern Hills. 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).


Stokenchurch Gap, a cutting built to carry the M40 motorway through a section of the Chiltern Hills

Several transport routes pass through the Chiltern Hills in natural or human-made corridors. There are also over 2,000 km (1,200 mi) of public footpaths in the Chiltern Hills, including long-distance trackways such as the Icknield Way and The Ridgeway.[10] The M40 motorway passes through the Chiltern Hills 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 Railway via High Wycombe and Princes Risborough, the London to Aylesbury Line via Amersham, the West Coast Main Line via Berkhamsted, 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 Chiltern Hills with London Paddington. The Chinnor and Princes Risborough Railway is a preserved line.

High Speed 2 (HS2) will pass underneath the Chiltern Hills in the Chiltern tunnel. This tunnel, the longest under construction on the HS2 route, will be 16 km (9.9 miles) in length.[11] The Conservation Board has made clear it was opposed to the routing of HS2 through the Chiltern Hills AONB.[12][13]

Bus services are provided by Arriva Shires & Essex and Carousel Buses. Air corridors from Luton Airport pass over the Chiltern Hills.

Apart from the River Thames, there are no navigable rivers. The Grand Union Canal passes through the Chiltern Hills between Berkhamsted and Marsworth following the course of the Gade and Bulbourne. Also, after crossing a watershed, the Ouzel is partly in the Chiltern Hills.


Bottle kiln, Nettlebed, probably from the late 17th century
Watlington Town Hall

During the Iron Age, the Chiltern ridge provided a relatively safe and easily navigable route across southern Britain. 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.[14]

Before the 18th century, the population lived dispersed across the largely rural landscape of the Chiltern Hills 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 in the first half of the 20th century and continued throughout the 20th century.

In 1965 almost half of the Chiltern Hills was designated[citation needed] as an Area of Outstanding Natural Beauty (AONB).

List of towns and villages in the Chiltern Hills

Strip parishes associated with the Chiltern Hills

The western edge of the Chiltern Hills is notable for ancient strip parishes, elongated parishes with villages in the flatter land below the escarpment, and woodland and summer pastures in the higher land.[2]

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.[1] The area was once (and still is to a lesser degree) renowned for its chair-making industry,[1] 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 Chiltern Hills. 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 Chiltern Hills area. Over-exploitation has possibly led to the disappearance of some streams over long periods.[15]

In a region without building stone, local clay provided the raw materials for brick manufacture. Timber and flint were also used for construction.

Mediaeval strip parishes reflected the diversity of land from clay farmland, through wooded slopes to downland. Their boundaries were often drawn to include a section of each type of land, resulting in an irregular county boundary. These have tended to be smoothed out by successive reorganisations.

As people have come to appreciate the open country, the area has become a visitor destination and the National Trust has acquired land to preserve its character, for example at Ashridge, near Tring. In places, with the reduction of sheep grazing, action has been taken to maintain open downland by suppressing the natural growth of scrub and birch woodland. In the 1920s and 1930s, the Youth Hostels Association established several youth hostels for people visiting the hills.

The hills have been used as a location for telecommunication relay stations such as Stokenchurch BT Tower and that at Zouches Farm.


Vernacular architecture of the Chilterns is preserved at the Chiltern Open Air Museum

The Chiltern Hills is an Area of Outstanding Natural Beauty (AONB) and so enjoys special protection from major developments, which should not take place in such areas except in exceptional circumstances. This protection applies to major development proposals that raise issues of national significance.[16] In 2000 the government confirmed that the landscape qualities of AONBs are equivalent to those of National Parks, and that the protection given to both types of area by the land use planning system should also be equivalent.

Chilterns Conservation Board

The Chiltern Hills Conservation Board was established by Parliamentary Order in July 2004. It is an independent body comprising 27 members drawn from the relevant local authorities and from those living in local communities within the Chiltern AONB area.

The Board's purposes are set out in Countryside and Rights of Way Act 2000: In summary these are:- First, to conserve and enhance the natural beauty of the AONB, and increase the understanding and enjoyment by the public of the special qualities of the AONB. Second, while taking account of the first purpose, to foster the economic and social wellbeing of local communities within the AONB. Third, to publish and promote the implementation of a management plan for the AONB.[17]

In contrast to National Parks, The Chiltern Hills – as other AONBs – do not possess their own planning authority. The Board has an advisory role on planning and development matters and seeks to influence the actions of local government by commenting upon planning applications.[18]

The local authorities (two County Councils, three Unitary Authorities and four District and Borough Councils) are expected to respect the area's status as a designated Area of Outstanding Natural Beauty.


Examples of historical architecture in the Chiltern region are preserved at the Chiltern Open Air Museum near Chalfont St Giles. This open-air folk museum contains reconstructed buildings which might otherwise have been destroyed or demolished as a result of redevelopment or road construction.[19][20]

Chiltern Hundreds

Main article: Resignation from the British House of Commons

The Chiltern Hills includes the Chiltern Hundreds. By established custom, Members of Parliament (MPs) in the House of Commons of the United Kingdom, who are prohibited from resigning their seats directly, may apply for the Stewardship of the Chiltern Hundreds as a device to enable their departure from the House.

List of hills

Hills in The Chiltern Hills more than 200 metres in elevation and with more than 30 metres of topographic prominence are listed from southwest to northeast.[21]

Hill Elevation (m) Prominence (m) OS grid reference
Bald Hill 257 125 SU728957
Widdenton Park Hill 203 35 SU817917
Lodge Hill 209 45 SP794000
Whiteleaf Hill 247 63 SP823034
Pulpit Hill 248 56 SP831050
Beacon Hill 230 33 SP835060
Coombe Hill 260 108 SP849066
Wendover Woods 267 180 SP890090
Aldbury Nowers 222 41 SP952136
Clipper Down 249 123 SP965151
Dunstable Downs 243 105 TL008194
Blow's Down 212 48 TL034214

See also


  1. ^ a b c d Chisholm, Hugh, ed. (1911). "Chiltern Hills" . Encyclopædia Britannica. Vol. 6 (11th ed.). Cambridge University Press. p. 163.
  2. ^ a b Hepple, Leslie; Doggett, Alison (1971). The Chilterns. England: Phillimore & Co Ltd. ISBN 0-85033-833-6.
  3. ^ a b c The Changing Landscape of the Chilterns Archived 3 March 2016 at the Wayback Machine Chilterns AoNB, Accessed 19 February 2012
  4. ^ Chiltern Society, The Chilterns Archived 7 September 2011 at the Wayback Machine.
  5. ^ a b c 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 ISBN 978-1-86239-200-7
  6. ^ a b 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. ISBN 0-412-44510-7
  7. ^ Hepple, Leslie (1992). The Chilterns. Chichester, Sussex: Phillimore & Co., Ltd. p. 16. ISBN 085033-833-6.
  8. ^ "Natural England". Archived from the original on 8 October 2011. Retrieved 24 June 2011.
  9. ^ B.S. Nau, C. R. Boon, and J. P. Knowles, Bedfordshire Wildlife, Castlemead, 1987, ISBN 0-948555-05-X, page 71.
  10. ^ DidYouKnow.pdf[permanent dead link] Chilterns AoNB, Accessed 19 February 2012
  11. ^ "Chiltern Tunnel". High Speed 2. Retrieved 4 February 2022.
  12. ^ Chilterns Conservation Board – statement objecting to HS2, Accessed 12 December 2012
  13. ^ Chilerns AoNB website – HS2, Accessed 20 February 2012
  14. ^ Ekwall (1940). The Concise Oxford Dictionary of English Place-names (second ed.). Oxford: Clarendon Press. p. 99. 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)
  15. ^ Chess Valley Association, Accessed 4 September 2014
  16. ^ "Planning Policy Statement 7: Sustainable Development in Rural Areas" (PDF). Archived from the original (PDF) on 23 November 2009. Retrieved 25 March 2010.
  17. ^ Chiltern Conservation Board – Our Role Archived 4 April 2023 at the Wayback Machine, Accessed 10 December 2012
  18. ^ "The Chilterns AONB – Planning & Development". Archived from the original on 4 April 2023. Retrieved 5 March 2021.
  19. ^ "Historic Buildings". Chiltern Open Air Museum. Archived from the original on 28 January 2021. Retrieved 27 April 2022.
  20. ^ Matthews, Helen; Matthews, Neil (15 February 2019). Slow Travel: The Chilterns & the Thames Valley. Bradt Travel Guides. pp. 103–104. ISBN 978-1-78477-613-8. Retrieved 27 April 2022.
  21. ^ "Marilyn Regions". Retrieved 22 June 2020.