Slough () is a town in the unitary authority of the same name in Berkshire, England, bordering Greater London. It lies in the Thames Valley, west of central London and north-east of Reading, at the intersection of the M4, M40 and M25 motorways. It is part of the historic county of Buckinghamshire. In 2020, the built-up area subdivision had an estimated population of 164,793. In 2011, the district had a population of 140,713. Slough's population is one of the most ethnically diverse in the United Kingdom, attracting people from across the country and the world for labour since the 1920s, which has helped shape it into a major trading centre. In 2017, unemployment stood at 1.4%, one-third the UK average of 4.5%. Slough has the highest concentration of UK HQs of global companies outside London. Slough Trading Estate is the largest industrial estate in single private ownership in Europe, with over 17,000 jobs in 400 businesses. Blackberry, McAfee, Burger King, DHL, Telefonica and Lego have head offices in the town. History The name was first recorded in 1195 as Slo. 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 (later absorbed into Slough), 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 to Windsor & Eton Central, opposite Windsor Castle, for Queen Victoria's convenience. Slough has 96 listed buildings. There are Four Grade I: St Laurence's Church (Upton), St Mary the Virgin Church, Langley, Baylis House and Godolphin Court Seven Grade II*: St Mary's Church (Upton-cum-Chalvey), Upton Court, the Kederminster and Seymour Almshouses in Langley, St Peter's Church (Chalvey), Ostrich Inn (Colnbrook) and