The Pinn is a suburban, outer west London river. It has dendritic headwaters, the furthest is considered its sourcein

Harrow Weald Harrow Weald is a suburban district in Greater London, England. Located about north of Harrow, London, Harrow, Harrow Weald is formed from a leafy 1930s suburban development along with ancient woodland of Harrow Weald Common. It forms part of ...

. Its

confluence In geography, a confluence (also ''conflux'') occurs where two or more watercourses join to form a single channel (geography), channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main ...

with Frays River makes it a

tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...

of the

Colne Colne () is a market town and civil parishes in England, civil parish in the Borough of Pendle in Lancashire, England. The town is northeast of Nelson, Lancashire, Nelson, northeast of Burnley and east of Preston, Lancashire, Preston. The ...

. It is one of three principal rivers wholly in the historic county of

Middlesex Middlesex (; abbreviation: Middx) is a Historic counties of England, former county in South East England, now mainly within Greater London. Its boundaries largely followed three rivers: the River Thames, Thames in the south, the River Lea, Le ...

Route

The river runs through

Pinner Pinner is a suburb in the London Borough of Harrow, northwest London, England, northwest of Charing Cross, close to the border with Hillingdon, historically in the county of Middlesex. The population was 38,698 in 2021. Originally a mediaeval ...

, the northern halves of

Eastcote Eastcote is a suburban area in the London Borough of Hillingdon, in West London, west Greater London, London. In the Middle Ages, Eastcote was one of the three areas that made up the parish of Ruislip, under the name of Ascot. The name came fr ...

and

Ruislip Ruislip ( ) is a suburb in the London Borough of Hillingdon in northwest London. Prior to 1965 it was in Middlesex. Ruislip lies west-north-west of Charing Cross, London. The manor of Ruislip appears in the Domesday Book, and some of the ear ...

: the latter may be a notable rise-lip of land as 17th century maps often have the place name but likely derives from "rush leap" from the local width of the river. It then runs through

Ickenham Ickenham is an area in Greater London, forming the northern part of Uxbridge and within the London Borough of Hillingdon. While no major historical events have taken place in Ickenham, settlements dating back to the Roman occupation of Britai ...

and on to

Uxbridge Uxbridge () is a suburban town in west London, England, and the administrative headquarters of the London Borough of Hillingdon, northwest of Charing Cross. Uxbridge formed part of the parish of Hillingdon in the county of Middlesex. As part ...

, where it passes through the former grounds of

RAF Uxbridge RAF Uxbridge was a Royal Air Force (RAF) station in Uxbridge, within the London Borough of Hillingdon, occupying a site that originally belonged to the Hillingdon House estate. The British Government purchased the estate in 1915, three years b ...

and

Brunel University Brunel University of London (BUL) is a public research university located in the Uxbridge area of London, England. It is named after Isambard Kingdom Brunel, a Victorian engineer and pioneer of the Industrial Revolution. It became a university ...

. The Pinn continues on to Pield Heath and Cowley, passing under the

Grand Union canal The Grand Union Canal in England is part of the Canals of the United Kingdom, British canal system. It is the principal navigable waterway between London and the Midlands. Starting in London, one arm runs to Leicester and another to Birmi ...

before joining the Frays River, an

anabranch An anabranch is a section of a river or stream that diverts from the main channel or stem of the watercourse and rejoins the main stem downstream. Local anabranches can be the result of small islands in the watercourse. In larger anabranches, ...

of the Colne, at

Yiewsley Yiewsley ( ) is a large suburban village in the London Borough of Hillingdon, England, 2 miles (3 km) south of Uxbridge, the borough's commercial and administrative centre. Yiewsley was a chapelry in the ancient parish of Hillingdon, Middl ...

."Cowley: Introduction"
''A History of the County of Middlesex: Volume 3: Shepperton, Staines, Stanwell, Sunbury, Teddington, Heston and Isleworth, Twickenham, Cowley, Cranford, West Drayton, Greenford, Hanwell, Harefield and Harlington'' (1962), pp. 170-172. Institute of Historical Research, University of London. Retrieved 27 October 2008. During the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

only, the Pinn was dammed near

High Street for water for putting out fires from air raids. The middle and lower thirds of the course are between the Colne and Crane, all flowing south, thus making up parallel drainage.

Celandine Route

This is a walk through woodland, meadows and parks. It finishes at the Grand Union Canal towpath parallel to the Fray's River anabranch of the Colne.

Connections

A short walk east along the Slough Arm of the

Grand Union Canal The Grand Union Canal in England is part of the Canals of the United Kingdom, British canal system. It is the principal navigable waterway between London and the Midlands. Starting in London, one arm runs to Leicester and another to Birmi ...

connects. The Grand Union Canal towpath connects, linking in Brentford (east south-east), Watford and the Midlands (north), and the

Paddington Arm The Paddington Canal or Paddington Arm (also known as Paddington Branch) of the Grand Union Canal is a canal from Bull's Bridge in Hayes, Hillingdon, Hayes, west London, to Paddington in central London, England. Little Venice, London, Little Ven ...

(central London, east).

Water quality

All local sewerage runs to the distant Mogden Sewage Treatment Works discharging its treated waters to the

Tideway The Tideway is the part of the River Thames in England which is subject to tides. This stretch of water is downstream from Teddington Lock. The Tideway comprises the upper Thames Estuary including the Pool of London. Tidal activity Depending ...

. This spares the Pinn from the incident nitrogen, bleach (ammonia) and other chemical biohazards which many of its catchment homes and business use and/or discharge. The Pinn's flow is weak save for after moderate or heavy rain. Worn tyre and motor oil run-off is from some roadside drains at biohazardous levels, particularly below the

A40 road The A40 is a trunk road which runs between London and Goodwick (Fishguard), Wales, and officially called The London to Fishguard Trunk Road (A40) in all legal documents and Acts. Much of its length within England has been superseded by motorw ...

which is a trunk route of six lanes at this point (this becomes the

M40 motorway The M40 motorway links London, Oxford, and Birmingham in England, a distance of approximately . The motorway is dual three lanes except for junction 1A to junction 3 (which is dual four lanes) a short section in-between the exit and entry hig ...

to the west) – about of this slopes down to the river.

Citations and footnotes

External links