Botley Hill is a hill in

Surrey Surrey () is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Greater London to the northeast, Kent to the east, East Sussex, East and West Sussex to the south, and Hampshire and Berkshire to the wes ...

and is the highest point of the

North Downs The North Downs are a ridge of chalk hills in south east England that stretch from Farnham in Surrey to the White Cliffs of Dover in Kent. Much of the North Downs comprises two Area of Outstanding Natural Beauty, Areas of Outstanding Natural Be ...

, with a height of . The

Prime Meridian A prime meridian is an arbitrarily chosen meridian (geography), meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. On a spheroid, a prime meridian and its anti-meridian (the 180th meridian ...

crosses the hill.

Geography

Botley Hill is a Marilyn (a hill with

topographic prominence In topography, prominence or relative height (also referred to as autonomous height, and shoulder drop in US English, and drop in British English) measures the height of a mountain or hill's summit relative to the lowest contour line encircling ...

of at least 150m), and the third highest point in the county (after the peaks of

Leith Hill Leith Hill in southern England is the highest summit of the Greensand Ridge, approximately southwest of Dorking, Surrey and southwest of central London. It reaches above sea level, and is the second highest point in southeast England, aft ...

south of

Dorking Dorking () is a market town in Surrey in South East England about south-west of London. It is in Mole Valley, Mole Valley District and the non-metropolitan district, council headquarters are to the east of the centre. The High Street runs ro ...

and Gibbet Hill in

Hindhead Hindhead is a village in the Waverley, Surrey, Waverley district of the county of Surrey, England. It is the highest village in the county and its buildings are between and above sea level. The village forms part of the Haslemere parish. Situ ...

, both on the

Greensand Ridge The Greensand Ridge, also known as the Wealden Greensand, is an extensive, prominent, often wooded, mixed greensand/sandstone escarpment in south-east England. Forming part of the Weald, a former dense forest in Sussex, Surrey and Kent, it ...

). Botley Hill was a main surveying point for the

Anglo-French Survey (1784–1790) The Anglo-French Survey (1784–1790) was the geodetic survey to measure the relative position of the Royal Observatory, Greenwich, Royal Greenwich Observatory and the Paris Observatory via triangulation (surveying), triangulation. The English ...

which sought to precisely measure the relative positions of the

Royal Greenwich Observatory The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, temporarily moved south from Greenwich to Herstmonceux) is an observatory situated on a hill in G ...

and the

Paris Observatory The Paris Observatory (, ), a research institution of the Paris Sciences et Lettres University, is the foremost astronomical observatory of France, and one of the largest astronomical centres in the world. Its historic building is on the Left Ban ...

. This task was led by General

William Roy Major-General William Roy (4 May 17261 July 1790) was a Scottish military engineer, surveyor, and antiquarian. He was an innovator who applied new scientific discoveries and newly emerging technologies to the accurate geodetic mapping of Gr ...

. By coincidence Botley Hill lies due south of the Greenwich Observatory, as the

of the world passes over the top of the hill, just to the west of the summit. The summit lies at the edge of a water tower enclosure to the north of The Ridge, less than 1 km from the

North Downs Way The North Downs Way National Trail is a long-distance path in South East England, opened in 1978. It runs from Farnham in Surrey to Dover in Kent, past Guildford, Dorking, Merstham, Otford and Rochester, through the Surrey Hills National Lan ...

. Previously the location of the Marilyn was given as the trig point at TQ396553 as this is the highest point marked on current maps. However, the 1965 1"

Ordnance Survey The Ordnance Survey (OS) is the national mapping agency for Great Britain. The agency's name indicates its original military purpose (see Artillery, ordnance and surveying), which was to map Scotland in the wake of the Jacobite rising of ...

map shows a

spot height A spot height is an exact point on a map with an elevation recorded beside it that represents its height above a given datum.Whittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984, p. 506. . In the UK this is the Ordnan ...

of 882 feet at the site of the present water tower. A levelling survey confirmed the new location. To the south is

Oxted Oxted is a town and civil parish in the Tandridge District, Tandridge district of Surrey, England. It is at the foot of the North Downs, south-east of Croydon, west of Sevenoaks, and north of East Grinstead. Oxted is a commuter town and Ox ...

, which is the nearest railway station. It can be seen from the highest points in

Croydon Croydon is a large town in South London, England, south of Charing Cross. Part of the London Borough of Croydon, a Districts of England, local government district of Greater London; it is one of the largest commercial districts in Greater Lond ...

, skyscrapers in London, and for example from

Alexandra Palace Alexandra Palace is an entertainment and sports venue in North London, situated between Wood Green and Muswell Hill in the London Borough of Haringey. A listed building, Grade II listed building, it is built on the site of Tottenham Wood and th ...

Stanmore Stanmore is part of the London Borough of Harrow in Greater London. It is centred northwest of Charing Cross, lies on the outskirts of the London urban area and includes Stanmore Hill, one of the List of highest points in London, highest point ...

Hill,

Primrose Hill Primrose Hill is a Grade II listed public park located north of Regent's Park in London, England, first opened to the public in 1842.Mills, A., ''Dictionary of London Place Names'', (2001) It was named after the natural hill in the centre of t ...

Highgate Highgate is a suburban area of N postcode area, north London in the London Borough of Camden, London Boroughs of Camden, London Borough of Islington, Islington and London Borough of Haringey, Haringey. The area is at the north-eastern corner ...

and

Hampstead Hampstead () is an area in London, England, which lies northwest of Charing Cross, located mainly in the London Borough of Camden, with a small part in the London Borough of Barnet. It borders Highgate and Golders Green to the north, Belsiz ...

on the opposite side of the

Thames Basin The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the ...

.Image
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Notes

{{DEFAULTSORT:Botley Hill Marilyns of England Hills of Surrey