Southall formed part of the chapelry of Norwood in the ancient parish of Hayes, in the Elthorne hundred of Middlesex. The chapelry of Norwood had functioned as a separate parish since the Middle Ages. On 16 January 1891 the parish adopted the Local Government Act 1858 and the Southall Norwood Local Government District was formed. In 1894 it became the Southall Norwood Urban District. In 1936 the urban district was granted a charter of incorporation and became a municipal borough, renamed Southall. In 1965 the former area of the borough was merged with that of the boroughs of Ealing and Acton to form the London Borough of Ealing in Greater London.
The southern part of Southall (roughly south of the railway) used to be known as Southall Green (and a section of the main north-south road in the area is still called The Green) and was centred on the historic Tudor-styled Manor House which dates back to at least 1587. Little of the building is original but much dates back to the days when Southall Green was a quiet rural village.
The main east west road through the town is Uxbridge Road, though the name changes in the main shopping area to The Broadway and for an even shorter section to High Street. Uxbridge Road was part of the main London to Oxford stagecoach route for many years and remained the main route to Oxford until the building of the Western Avenue highway to the north of Southall in the first half of the 20th century. First horse drawn, then electric trams (until 1936) and, then, electric trolleybuses, gave Southall residents and workers quick and convenient transport along Uxbridge Road in the first half of the 20th century before they were replaced by standard diesel-engined buses in 1960.
The opening of the Grand Junction Canal (later renamed Grand Union Canal) as the major freight transport route between London and Birmingham in 1796 began a commercial boom, intensified by the arrival of Brunel's Great Western Railway in 1839, leading to brick factories, flour mills and chemical plants which formed the town's commercial base. In 1877, the Martin Brothers set up a ceramics factory in an old soap works next to the canal and until 1923, produced distinctive ceramics now known and collected as Martinware.
A branch railway line from Southall railway station to the Brentford Dock on the Thames was also built by Isambard Kingdom Brunel in 1856. It features one of his (impressive for the period) engineering works, the Three Bridges (although it is still often referred to on maps by the original canal crossing name of Windmill Bridge) where Windmill Lane, the railway and the Grand Union Canal all intersect – the canal being carried over the railway line cutting below in a cast-iron trough and a new cast-iron road-bridge going over both. It is listed as a Scheduled Ancient Monument.
Otto Monsted, a Danish margarine manufacturer, built a large factory at Southall in 1894. The factory was called the Maypole Dairy, and eventually grew to become one of the largest margarine manufacturing plants in the world, occupying a 28 hectares (69 acres) site at its peak. The factory also had its own railway sidings and branch canal. The Maypole Dairy Company was later acquired by Lever Brothers who, as part of the multinational Unilever company, converted the site to a Wall's Sausages factory which produced sausages and other meat products through until the late 1970s.
The Quaker Oats Company built a factory in Southall in 1936. Part of the operation that made pet foods was sold to Spiller's in 1994, and the remainder to Big Bear Group in 2006. The site continues to produce brands such as Sugar Puffs. Other engineering, paint and food processing factories prospered for many years, mostly alongside the railway and/or canal.
Southall was the home of Southall Studios, one of the earliest British film studios. It played a historic role in film-making from its creation in 1924 to its closure in 1959.
A major gas works manufacturing town gas was located between the railway and the canal. In 1932 a large gasholder was built which has been a noticeable landmark ever since as it can be easily observed from a long distance away. Painted on the north east side of the gasholder are the large letters 'LH' and an arrow to assist pilots locate Heathrow Airport's (now closed) runway 23 when making visual approaches. The letters were painted in the mid 1960s after a number of pilots became confused between Heathrow and the nearby RAF Northolt (which has a similar, though smaller, gasholder under its approach at Harrow).
Southall is primarily a South Asian residential district. In 1950, the first group of South Asians arrived in Southall, reputedly recruited to work in a local factory owned by a former British Indian Army officer. This South Asian population grew, due to the closeness of expanding employment opportunities such as London Heathrow Airport. There are ten Sikh Gurdwaras in Southall. The Gurdwara Sri Guru Singh Sabha, which opened in 2003, is one of the largest Sikh gurdwaras outside India, and it won the Ealing Civic Society Architectural Award in 2003. There are two large Hindu 'Mandir' temples, the Vishnu Hindu Mandir on Lady Margaret Road and the Ram Mandir in Old Southall. There are more than ten Christian churches including 5 Anglican, one Roman Catholic (St Anselm's Church), Baptist, Methodist and several Pentecostal or Independent.
The signs on the main railway station are bilingual in English and Gurmukhi, which is one of the written scripts of Punjabi.