Trafford Park is almost entirely surrounded by water; the Bridgewater Canal forms its southeastern and southwestern boundaries, and the Manchester Ship Canal, which opened in 1894, its northeastern and northwestern. Hooley's plan was to develop the Ship Canal frontage, but the canal was slow to generate the predicted volume of traffic, so in the early days the park was largely used for leisure activities such as golf, polo and boating. British Westinghouse was the first major company to move in, and by 1903 it was employing about half of the 12,000 workers then employed in the park, which became one of the most important engineering facilities in Britain.
Trafford Park was a major supplier of materiel in the First and Second World Wars, producing the Rolls-Royce Merlin engines used to power both the Spitfire and the Lancaster. At its peak in 1945, an estimated 75,000 workers were employed in the park. That number began to decline in the 1960s as companies closed in favour of newer, more efficient plants elsewhere. By 1967 employment had fallen to 50,000, and the decline continued throughout the 1970s. The new generation of container ships was too large for the Manchester Ship Canal, which led to a further decline in Trafford Park's fortunes. The workforce had fallen to 15,000 by 1976, and by the 1980s industry had virtually disappeared from the park.
The Trafford Park Urban Development Corporation, formed in 1987, reversed the estate's decline. In the 11 years of its existence, the park attracted 1,000 companies, generating 28,299 new jobs and £1.759 billion of private-sector investment. As of 2008, there were 1,400 companies within Trafford Park, employing an estimated 35,000 people.
Until the industrial development of the park began in the late 19th century, much of the area now known as Trafford Park was a "beautifully timbered deer park". Its 1,183 acres (4,790,000 m2) comprised flat meadows and grassland, and an inner park containing a tree-lined avenue leading from an entrance lodge at Barton-upon-Irwell. It was the ancestral estate of the de Trafford family, one of the most ancient in England, and then one of the largest landowners in Stretford. The family acquired the lands around Trafford in about 1200, when Richard de Trafford was given the lordship of Stretford by Hamon de Massey, 4th Baron of Dunham. Some time between 1672 and 1720, the de Traffords moved from the home they had occupied since 1017, in what is now known as Old Trafford, to what was then called Whittleswick Hall, which they renamed Trafford Hall. Their new home was a little to the east of where Tenax Circle is today, at the northwestern end of Trafford Park Road.
Trafford Park contained the hall, its grounds, and three farms: Park Farm, Moss Farm, and Waters Meeting Farm. From the original three entrance lodges to the park, at Throstle Nest, Barton-upon-Irwell and Old Trafford, only the latter has survived, having been relocated from its original position opposite what is today the White City retail park to become the entrance to Gorse Hill Park.
In 1761, a section of the Bridgewater Canal was built along the southeast and southwest sides of Trafford Park. The canal along with the River Irwell, which marked the estate's northeast and northwest boundaries, gave the park its present-day "island-like" quality. In about 1860, an 8-acre (32,000 m2) ornamental lake was dug in the north of the park, close to the River Irwell.
A meeting held in 1882 at the Didsbury home of engineer Daniel Adamson began the estate's transformation, with the creation of the Manchester Ship Canal committee. Sir Humphrey de Trafford was an implacable opponent of the proposed canal, objecting that, amongst other things, it would bring polluted water close to his residence, interfere with his drainage, and render Trafford Hall uninhabitable, forcing him to "give up his home and leave the place". Despite Sir Humphrey's opposition the Ship Canal Bill became law on its third passage through Parliament, on 6 August 1885. Construction began in 1888, more than two years after Sir Humphrey's death, although a 9-foot-high (2.7 m) wall was built between the canal and the park, so as to block it off from view. Two wharves were also built, for the exclusive use of the de Traffords.