River Brent

Brent
River
River Brent at Brentford
Country	England
Counties	Greater London
Districts / Boroughs	London Borough of Barnet, London Borough of Brent, London Borough of Ealing, London Borough of Hounslow
Tributaries
- left	Dollis Brook, Decoy Brook, Clitterhouse Brook, Silk Stream, Wealdstone Brook, Gadder brook
- right	Mutton Brook, Peggy Back's (subterranean) drain
Towns	Brent Cross, Greenford, Hanwell
Mouth	River Thames
- location	Brentford, Greater London
Length	29 km (18 mi)
Discharge	for Costons Lane, Greenford
- average	1.32 m3/s (47 cu ft/s)
- max	42.9 m3/s (1,515 cu ft/s) 12 October 1993
- min	0.19 m3/s (7 cu ft/s) 3 August 1995
Discharge elsewhere (average)
- Monks Park	1.00 m3/s (35 cu ft/s)
- Brent Cross	0.34 m3/s (12 cu ft/s)

The River Brent is a river in west and northwest London, England, and a tributary of the River Thames. 17.9 miles (29 km) in length, it rises in the Borough of Barnet and flows in a generally south-west direction before joining the Tideway stretch of the Thames at Brentford.

A letter from the Bishop of London in AD 705 suggesting a meeting at Breġuntford, now Brentford, is the earliest record of this place and probably therefore that of the river, suggesting that the name may be related to the Celtic *brigant- meaning "high" or "elevated" perhaps linked to the goddess Brigantia

The River Thames can first be identified as a discrete drainage line as early as 58 million years ago, in the Thanetian stage of the late Palaeocene epoch. Until around half a million years ago, the Thames flowed on its existing course through what is now Oxfordshire, before turning to the north east through Hertfordshire and East Anglia to reach the North Sea near Ipswich. At this time the river system headwaters lay in the English West Midlands and may, at times, have received drainage from the North Wales Berwyn Mountains. The river Brent and its valley's formation was the result of glacial action during the ice age which had started some 500,000 years ago; in that period of the early neogene, the major drainage channel for this part of England, the proto-Thames, was 25 miles (40 km) north of Brentford and travelled east via the St Albans depression. The River Brent and adjacent tributaries the Colne Brook and those downstream such as the River Lea either flowed into this more northern Thames or formed the early course of the present day river Thames.