Botley Hill is a hill in Surrey 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 Areas of Outstanding Natural Beauty (AONBs): the Surrey Hills a ...

with a height of . The

Prime Meridian A prime meridian is an arbitrary meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great ...

crosses the hill.

Geography

Botley Hill is a Marilyn (a hill with

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

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, after ...

south of Dorking and Gibbet Hill in

Hindhead Hindhead is a village in Surrey, England. It is the highest village in Surrey, with buildings at between 185 and 253 metres above sea level. It is best known as the location of the Devil's Punch Bowl, a beauty spot and site of special scienti ...

, 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 r ...

). 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 Greenwich Observatory and the Paris Observatory via triangulation. The English operations, executed by William Roy, consisted of the measureme ...

which sought to precisely measure the relative positions of the Royal Greenwich Observatory and the Paris Observatory. 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 ...

. 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 southern England, opened in 1978. It runs from Farnham to Dover, past Guildford, Dorking, Merstham, Otford and Rochester, along the Surrey Hills Area of Outstanding Natural Be ...

. 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 Ordnance Survey (OS) is the national mapping agency for Great Britain. The agency's name indicates its original military purpose (see ordnance and surveying), which was to map Scotland in the wake of the Jacobite rising of 1745. There was a ...

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 Ordna ...

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 of Surrey, England, at the foot of the North Downs. It is south south-east of Croydon in Greater London, west of Sevenoaks in Kent, and north of East Grinstead in West Sussex. Oxted ...

, 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 local government district of Greater London. It is one of the largest commercial districts in Greater London, with an extensi ...

, skyscrapers in London, and for example from Alexandra Palace, Stanmore 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 ...

Highgate Highgate ( ) is a suburban area of north London at the northeastern corner of Hampstead Heath, north-northwest of Charing Cross. Highgate is one of the most expensive London suburbs in which to live. It has two active conservation organisat ...

and Hampstead 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 R ...

.http://www.viewfinderpanoramas.org/panoramas/ENG/Alexandra.gif

Notes

{{Surrey Hills AONB Marilyns of England Hills of Surrey