Historically part of Cheshire, Altrincham was established as a market town in 1290, a time when the economy of most communities was based on agriculture rather than trade, and there is still a market in the town. Further socioeconomic development came with the extension of the Bridgewater Canal to Altrincham in 1765 and the arrival of the railway in 1849, stimulating industrial activity in the town. Outlying villages were absorbed by Altrincham's subsequent growth, along with the grounds of Dunham Massey Hall, formerly the home of the Earl of Stamford, and now a tourist attraction with three Grade I Listed Buildings and a deer park.
Altrincham today is an affluent commuter town, partly because of its transport links. The town has a strong middle-class presence; there has been a steady increase in Altrincham's middle classes since the 19th century. It is also home to Altrincham F.C. and three ice hockey clubs: Manchester Storm, Altrincham Aces and Trafford Tornados.
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.
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 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.