Chertsey Lock is a lock

Lock (water transport)

A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...

 on the River Thames

River Thames

The River Thames flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford,...

 in England, on the northern Middlesex bank near Chertsey

Chertsey

Chertsey is a town in Surrey, England, on the River Thames and its tributary rivers such as the River Bourne. It can be accessed by road from junction 11 of the M25 London orbital motorway. It shares borders with Staines, Laleham, Shepperton, Addlestone, Woking, Thorpe and Egham...

 (which is on the opposite side of the river) in north-west Surrey

Surrey

Surrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...

. The lock is about 200 yards upstream of the picturesque Chertsey Bridge

Chertsey Bridge

Chertsey Bridge is a road bridge across the River Thames in England, connecting Chertsey to low-lying riverside meadows in Laleham, Surrey. It is situated 550 yards downstream from the M3 motorway bridge over the Thames and is close to Chertsey Lock on the reach above Shepperton Lock.The bridge is...

. It was first built by the City of London

City of London

The City of London is a small area within Greater London, England. It is the historic core of London around which the modern conurbation grew and has held city status since time immemorial. The City’s boundaries have remained almost unchanged since the Middle Ages, and it is now only a tiny part of...

 Corporation in 1813.

The lock adjoins a small thin island connecting to Chertsey Weir, which is not pedestrianised.

History

There used to be problems upstream of the lock's position because of the shallows known as Laleham Gulls, and various proposals were put forward to resolve them. There was a survey for a lock in 1793, but it was disallowed by parliament. In 1805 there was another proposal for a cut along the length of the current reach, with a pound lock at the lower end, but this was resisted by local landowners. A lock was authorised by parliament in 1810 a short way upstream, but when Lord Lucan asked to have the lock out of his view, a new Act in 1812 authorised it at the present lower site. The lock was opened in 1813 with the lock-house effectively on the Middlesex bank (although technically in Surrey because the course of the stream had been altered. The lock was lengthened in 1893 and again in 1913. It was then built with two compartments, but the centre gates have since been removed.

Access to the lock

The lock is easily accessible, being on the Middlesex bank, immediately adjacent to Thames Side road and a short distance from Chertsey Bridge and the Kingfisher pub.

Reach above the lock

Shortly upstream of the lock, the river is crossed by the M3 Chertsey Bridge

M3 Chertsey Bridge

The M3 Chertsey Bridge is a motorway bridge in England built in the 1970s.The bridge carries the M3 motorway across the River Thames on the reach above Chertsey Lock. It is 500 yards upstream of the lock and Chertsey Bridge, a historic bridge over the river...

 carrying the M3 motorway

M3 motorway

The M3 motorway runs in England for approximately from Sunbury-on-Thames, Surrey, to Southampton, Hampshire and forms an unsigned section European route E05. It is dual three lanes as far as Junction 8 near Basingstoke and then dual two lane until Junction 9 near Winchester and then dual three...

 high overhead. The Middlesex bank has gravel pits out of sight and then park land until it reaches Laleham

Laleham

Laleham is a village in the borough of Spelthorne, in the county of Surrey in South East England and adjoins Staines. It is within the historic boundaries of Middlesex. To its south is Laleham Park by the River Thames, across green belt farmland to its north and south east are Ashford and...

, where there are riverside houses. From an inlet at Laleham, 200 million impgals (909,218 m³) of water are pumped into the Queen Mary Reservoir

Queen Mary Reservoir

The Queen Mary Reservoir is one of the largest of London's reservoirs located in the Staines/Sunbury area of West London within the borough of Spelthorne in Surrey. It lies south of the A308 and west of the M3 motorway...

 each day.
The Surrey bank is wild and open with a very small reservoir and pumping station beyond it. There is then a stretch of housing interspersed with boatyards, until short of Penton Hook. Before Penton Hook Lock, the backwater curves round Penton Hook Island

Penton Hook Island

Penton Hook Island is an island in the River Thames in England adjacent to Penton Hook Lock, near Laleham, Surrey. At this point the natural course of the river makes a large loop or "hook" round the island, although this is now closed off by the weir...

 to some marinas. This is the start point of the Abbey River

Abbey River

The Abbey River is a backwater of the River Thames in England, near Chertsey, Surrey. It runs from behind Penton Hook Island to below Chertsey Lock....

backwater which rejoins the Thames below Chertsey Lock. Burway Rowing Club is based at Thameside at Laleham on the reach and Burway Junior Regatta and Burway Head races take place from the area beneath the M3 Motorway Bridge.