Historically, the larger part of the present-day Slough area was formerly in Buckinghamshire with a small part of the borough a part of Middlesex. Slough is home to the Slough Trading Estate, which, coupled with extensive transport links, makes it an important business centre in South East England. It is the largest industrial estate in single private ownership in Europe. The town straddles the A4 Bath Road (it becomes the Great West Road closer to London) and the Great Western Main Line railway, west of central London. At the 2001 census, the population of Slough was 119,070 (140,200 in 2011) and the borough area was the most ethnically diverse local authority area outside London in the United Kingdom. Slough has the highest proportion of religious adherents in England.
In 1974 county boundaries were changed and Slough became a borough within the county of Berkshire, England. In 1998 Berkshire organized its local government structure into unitary authorities, one of which was Slough Borough.
The first recorded uses of the name occur as Slo in 1196, Sloo in 1336, and Le Slowe, Slowe or Slow in 1437. It first seems to have applied to a hamlet between Upton to the east and Chalvey to the west, roughly around the "Crown Crossroads" where the road to Windsor (now the A332) met the Great West Road. The Domesday Survey of 1086 refers to Upton, and a wood for 200 pigs, worth £15. During the 13th century, King Henry III had a palace at Cippenham. Parts of Upton Court were built in 1325, while St Mary the Virgin Church in Langley was probably built in the late 11th or early 12th century, though it has been rebuilt and enlarged several times.
From the mid-17th century, stagecoaches began to pass through Slough and Salt Hill, which became locations for the second stage to change horses on the journey out from London. By 1838 and the opening of the Great Western Railway, Upton-cum-Chalvey's parish population had reached 1,502. In 1849, a branch line was completed from Slough station to Windsor and Eton Central railway station, opposite Windsor Castle, for the Queen's convenience.
Slough has 96 listed buildings. There are
1918 saw a large area of agricultural land to the west of Slough developed as an army motor repair depot, used to store and repair huge numbers of motor vehicles coming back from the battlefields of the First World War in Flanders. In April 1920, the Government sold the site and its contents to the Slough Trading Co. Ltd. Repair of ex-army vehicles continued until 1925, when the Slough Trading Company Act was passed allowing the company (renamed Slough Estates Ltd) to establish an Industrial Estate. Spectacular growth and employment ensued, with Slough attracting workers from many parts of the UK and abroad.
During World War II, Slough experienced a series of air raids, mostly in October 1940 (the largest number of people, five, dying as a result of one on the 13th), and an emergency hospital treating casualties from London was set up in Slough. Local air raid deaths and deaths at the hospital account for the 23 civilian lives recorded lost in the borough area.
After the War, several further large housing developments arose to take large numbers of people migrating from war-damaged London.
The Town Hall has since been torn down and replaced by a multi-storey apartment block.