Trafford is a metropolitan borough of Greater Manchester, England, with an estimated population of 241,025 in 2024. It covers 106 square kilometres (41 sq mi) and includes the towns of Altrincham, Stretford, Urmston, Partington and Sale. The borough was formed in 1974 as a merger of six former districts and part of a seventh. The River Mersey flows through the borough, separating North Trafford from South Trafford, and the historic counties of Lancashire and Cheshire. Trafford is the seventh-most populous district in Greater Manchester.

There is evidence of Neolithic, Bronze Age, and Roman activity in the area, two castles – one of them a Scheduled Ancient Monument – and over 200 listed buildings. In the late 19th century, the population rapidly expanded with the arrival of the railway. Trafford is the home of Manchester United F.C. and Lancashire County Cricket Club, as well as Altrincham F.C. and Trafford F.C. The Imperial War Museum North, opened in 2002, is located in the borough.

Trafford has a strong economy with low levels of unemployment and contains both Trafford Park industrial estate and the Trafford Centre, a large out-of-town shopping centre. Apart from the City of Manchester, Trafford is the only borough in Greater Manchester to be above the national average for weekly income. Socially, the area includes both working class and middle class areas like Bowdon and Hale. In Parliament, Trafford is represented by three constituencies: Stretford and Urmston; Altrincham and Sale West; and Wythenshawe and Sale East, which mainly covers neighbouring Manchester.

The borough was formed on 1 April 1974 under the Local Government Act 1972, covering the area of six former districts which were abolished at the same time, as well as four civil parishes from a seventh abolished district:

‡ Parishes from Bucklow Rural District

Stretford and Urmston had been in the administrative county of Lancashire prior to the 1974 reforms, whilst all the others had been in the administrative county of Cheshire. The new district was awarded borough status from its creation, allowing the chairman of the council to take the title of mayor.

The choice of the name Trafford for the borough was a "compromise between Altrincham, Stretford and Sale", and "seemed to have wide support". A Liberal councillor for the Municipal Borough of Sale suggested "Crossford ... whilst "Watlingford" was suggested by councillors in Hale, after the supposed name of an ancient Roman road in the district. Those names were rejected in favour of Trafford, because of the district's "famous sports venue, a major employer as well as historic associations", referring to Old Trafford (cricket and football), Trafford Park and the de Trafford baronets respectively.

As a place name, Trafford is an Anglo-French version of Stratford, deriving from the Old English words stræt (street, more specifically a Roman road) and ford (crossing). The Metropolitan Borough of Trafford has existed since 1974, but the area it covers has a long history. Neolithic arrowheads have been discovered in Altrincham and Sale, and there is evidence of Bronze Age habitation in Timperley. Fragments of Roman pottery have been found in Urmston, and Roman coins have been found in Sale. The Roman road between the legionary fortresses at Chester (Deva Victrix) and York (Eboracum) crosses Trafford, passing through Stretford, Sale, and Altrincham. The settlements in Trafford have been based largely around agriculture, although Altrincham was founded as a market town in the mid 13th century. Although the Industrial Revolution affected Trafford, the area did not experience the same rate of growth as the rest of Greater Manchester. A 100% increase in population in the Trafford area between 1841 and 1861 was a direct result of an influx due to the construction of the Manchester, South Junction and Altrincham Railway, which allowed residents to commute more easily from Trafford into Manchester. The area developed its own centres of industry in Broadheath (founded in 1885) and Trafford Park (founded in 1897). They have since declined, although Trafford Park still employs 40–50,000 people. Today, Trafford is mostly a commuter area. The borough was formed on 1 April 1974 by the Local Government Act 1972 as one of the ten metropolitan districts of Greater Manchester.