Area: 32.54 km≤ 

Slough (pronounced [sla?]) is a town and unitary authority (Borough of Slough) in Berkshire in the South East England region of the UK. In the 2001 census the population was 119,070 (est. 122,000 in 2006). It is one of the most ethnically diverse towns in the UK, situated some 22 miles (35 km) west of central London and 20 miles (32 km) east of Reading.

It is home to the Slough Trading Estate, the UK's first such estate, the largest in single ownership, and one of the largest in Europe overall. This, coupled with extensive transport links, makes it one of the most important business centres in the south east of England. It is also home to the main campus of Thames Valley University.

The town is situated just to the west of Greater London. Proximate towns include Windsor to the south, Maidenhead to the west, Uxbridge to the northeast and Bracknell to the southwest.

Most of the area was traditionally part of Buckinghamshire and formed over many years by the amalgamation of villages along the Great West Road between London and Bath and Bristol. The first recorded uses of the name occur as Slo in 1196, Sloo in 1336, and Le Slowe, Slowe or Slow in 1437. The name may have derived from the various sloughs in the area; although some people think it may refer instead to Sloe bushes growing in the vicinty. Pubs and Coaching Inns grew up along the Great West Road to service the traffic between London and the West. Most people in the area lived in the joint parish of Upton and Chalvey, termed Upton-cum-Chalvey.

Montem Mound, located in Chalvey, is an ancient monument and its date of origin is not known. Eton College held its 'Eton Montem' ceremonies here until 1844. Montem Mound is also known as Salt Hill (originally Salts Hill). The area of Slough to the north of Chalvey and the Great West Road is also known as Salt Hill, as is Salt Hill Park, closely associated with Eton Montem. Salt Hill Park once boasted great iron gates, which were subsequently smelted as part of the war effort during World War II.

The Domesday Survey of 1086, refers to Upton, and a wood for 200 pigs, worth £15. Upton, with its Norman Church, was situated at the top of the slope from the river terrace - the various levels in the area having been formed in the Ice-Age.

In 1196, one Henry de Slo is mentioned in a Pipe Roll - the earliest documentary reference found to Slough.

During the 13th Century, King Henry III had a palace in Cippenham, the spot is still marked on modern maps as "Cippenham Moat". St Laurence's Church in Upton is around 900 years old and is the oldest building in Slough. Parts of Upton Court were built in 1325, while St Mary's Church in Langley was probably built in the late 11th or early 12th century, though it has been rebuilt and enlarged several times.

The astronomer William Herschel (1738 - 1822), and his sister Caroline, produced the first true map of the universe with a 40 foot long, 49 inch reflecting telescope he built in his garden in Windsor Road, Slough. A monument in Windsor Road commemorates his achievement. William married and is buried in St Laurence's Church, Slough. It is also believed that Joseph Haydn also visited Slough and met Herschel during his time there. According to one account, Haydn asked the esteemed astronomer for his opinion on the Biblical story of the seven days of Creation. Herschel's answer is unknown, but - so the story goes - Haydn went back to his lodgings and began to compose his famous oratorio The Creation.

The arrival of the railway in Slough in 1840 led to Queen Victoria making her first ever railway journey, from Slough station to Bishop's Bridge near Paddington, in 1842. In 1849, a branch line was completed from Slough Station to Windsor and Eton Central railway station for the Queen's greater convenience. Originally, the headmaster of Eton College, Dr. John Keate, had resisted efforts to place a station closer to Eton College than Slough, because he feared that it would "interfere with the discipline of the school, the studies and amusements of the boys, affecting the healthiness of the place, from the increase of floods, and endangering even the lives of boys."

On January 1, 1845, John Tawell, who had recently returned from Australia, murdered his lover, Sarah Hart, at Salt Hill in Slough by poisoning her with prussic acid. With various officials in chase, Tawell fled to Slough Station and boarded a train to Paddington. Fortunately, the electrical telegraph had recently been installed and so a message was sent ahead to Paddington with Tawell's details. Tawell was trailed and subsequently arrested, tried and executed for the murder at Aylesbury on March 28, 1845. This is believed to be the first time ever that the telegraph had been involved in the apprehension of a murderer.

In 1858, Charles Dickens rented a cottage on Church Street, under the name of Charles Tringham. This was most likely to be closer to his alleged mistress, Ellen Ternan. Dickens' second link to the town was his publisher, Richard Bentley, proprietor of the publishing firm 'Bentley's'.

In 1863 Slough became a local government area for the first time, when a Slough Local Board of Health was elected to represent what is now the central part of the modern Borough. This part of Upton-cum-Chalvey Parish became an urban sanitary district in 1875 and an Urban District Council area in 1894.

The Grand Junction Canal spur arrived in 1882, and, during the mid to late 1800s, the arrival of the large-scale brickmaking industry into Langley and the area north of the Great West Road, saw dramatic growth northwards encroaching on the very south of the parish of Stoke Poges. This new development saw the population centre of the town move northwards and the name Slough suppressed Upton-cum-Chalvey. The part of that parish not originally included in the Slough Urban District was incorporated in 1900.

The Church of England ecclesiastical parish of Upton-cum-Chalvey still exists, however, and includes the parish church of St Mary, and the churches of St Laurence (Upton) and St Peter (Chalvey). St Laurence's church recently installed an impressive set of stained-glass windows commemorating the work of Sir William Herschel, and remains an important historical building. Dating from Norman times, several walls bear testament to 'pudding-stone' construction, and overlooks Upton Court - now the administrative home of the Slough Observer newspaper - famously said to be haunted by a young woman in a blood-stained nightdress.

Slough has a number of listed buildings. There are four Grade I: St Laurence's church (Upton), St Mary the Virgin's church (Langley), Baylis House and Godolphin Court; seven Grade II*: St Mary's church, Upton Court, the Kederminster and Seymour Almshouses in Langley, St Peter's church (Chalvey), The Ostrich Inn (Colnbrook), King John's Palace (Colnbrook); and four Grade II listed milestones and listed buildings: Slough station, and Beech, Oak and Linden Houses at Upton Hospital.