Local evidence of prehistoric human activity exists in the form of two Neolithic arrowheads found in Altrincham, and further afield, a concentration of artefacts around Dunham. The remains of a Roman road, part of one of the major Roman roads in North West England connecting the legionary fortresses of Chester (Deva Victrix) and York (Eboracum), run through the Broadheath area. As it shows signs of having been repaired, the road was in use for a considerable period of time. The name Altrincham first appears as "Aldringeham", probably meaning "homestead of Aldhere's people". As recently as the 19th century it was spelt both Altrincham and Altringham.
A milestone along the Barton Bridge and Moses Gate turnpike road near Eccles, showing the spelling of "Altringham"
Until the Normans invaded England, the manors surrounding Altrincham were owned by the Saxon thegn Alweard; after the invasion they became the property of Hamon de Massey, though Altrincham is not mentioned in the Domesday Book. The earliest documented reference to the town is from 1290, when it was granted its charter as a Free Borough by Baron Hamon de Massey V. The charter, which exists and is held by Trafford MBC, allowed a weekly market to be held, and it is possible that de Massey established the town to generate income through taxes on trade and tolls. This suggests that Altrincham may have been a planned market town, unusual during the Middle Ages, when most communities were agricultural. Altrincham was probably chosen as the site of the planned town rather than Dunham – which would have been protected by Dunham Castle – because its good access to roads was important for trade.
Altrincham Fair became St James's Fair or Samjam in 1319 and continued until 1895. Fair days had their own court of Pye Powder (a corruption of the French for "dusty feet"), presided over by the mayor and held to settle disputes arising from the day's dealings. By 1348 the town had 120 burgage plots – ownership of land used as a measure of status and importance in an area – putting it on a par with the Cheshire town of Macclesfield and above Stockport and Knutsford. The earliest known residence in Altrincham was "the Knoll", on Stamford Street near the centre of the medieval town. A 1983 excavation on the demolished building, made by South Trafford Archaeological Group, discovered evidence that the house dated from the 13th or 14th century, and that it may have contained a drying kiln or malting floor. During the English Civil War, men from Altrincham fought for the Parliamentarian Sir George Booth. During the war, armies camped on nearby Bowdon Downs on several occasions.
In 1754, a stretch of road south of Altrincham, along the Manchester to Chester route, was turnpiked. Turnpikes were toll roads which taxed passengers for the maintenance of the road. Further sections were turnpiked in 1765 from Timperley to Sale, and 1821 from Altrincham to Stockport. The maintenance of roads passed to local authorities in 1888, although by then most turnpike trusts had already declined. The connection of the Bridgewater Canal to Altrincham in 1765 stimulated the development of market gardening, and for many years Altrincham was noted for its vegetables. By 1767, warehouses had been built alongside the canal at Broadheath, the first step in the development of Broadheath as an industrial area and the beginning of Altrincham's industrialisation. The canal was connected in 1776 to the River Mersey, providing the town not only with a water route to Manchester, but also to the Irish Sea.
Moves to connect the town to the UK's railway network gained pace in 1845, when the Act of Parliament for the construction of the Manchester South Junction and Altrincham Railway (MSJAR) was passed. The first train left Altrincham early on 20 July 1849, carrying 65 passengers. The MSJAR had two stations in the town: Altrincham, on Stockport Road, and Bowdon – though not actually in Bowdon – on Lloyd Street/Railway Street. Both were replaced in 1881 by Altrincham & Bowdon railway station on Stamford New Road. The London and North Western Railway's station at Broadheath, on the town's northern edge, was opened in 1854, while a further connection was created on 12 May 1862 by the Cheshire Midland Railway (later the Cheshire Lines Committee), who opened their line from Altrincham to Knutsford.
With its new railway links, Altrincham and the surrounding areas became desirable places for the middle classes and commuters to live. Professionals and industrialists moved to the town, commuting into Manchester. While some travelled daily by coach, the less well–to–do commuted by express or "flyer" barges from Broadheath. Between 1851 and 1881 the population increased from 4,488 to 11,250. Broadheath's industrial area, covering about 250 acres (1.0 km2), was founded in 1885 by Harry Grey, 8th Earl of Stamford, to attract businesses. By 1900 Broadheath had its own docks, warehouses and electricity generating station. The site's proximity to rail, canal and road links proved attractive to companies making machine tools, cameras and grinding machines. The presence of companies like Tilghmans Sand Blast, and the Linotype and Machinery Company, established Broadheath as an industrial area of national standing. By 1914, 14 companies operated in Broadheath, employing thousands of workers. One of those was the Budenberg Gauge Company. Linotype also created 172 workers' homes near its factory, helping cater for the population boom created by Broadheath's industrialisation. Between 1891 and 1901 the population of Altrincham increased by 35 per cent, from 12,440 to 16,831.
From the turn of the 20th century to the start of the Second World War, there were few changes in Altrincham. Although the town was witness to some of the Luftwaffe's raids on the Manchester area in the latter war, it emerged from the war relatively unscathed having lost only 23 civilian residents through enemy action, and as with the rest of Britain, experienced an economic boom. This manifested itself in the construction of new housing and the 1960s rebuilding of the town centre. However, during the 1970s employment at Broadheath declined by nearly 40 per cent.