Prehistoric and Roman periods
Towcester lays claim to being the oldest town in Northamptonshire and possibly, because of the antiquity of recent Iron Age finds in the town, to be one of the oldest continuously inhabited settlements in the country. There is evidence that it was settled by humans since the Mesolithic era (middle stone age). There is also evidence of Iron Age burials in the area.
In Roman Britain, Watling Street, now the A5 road, was built through the area and a garrison town called Lactodurum established on the site of the present-day town. Two candidate sites for the Battle of Watling Street, fought in 61AD, are located close to the town, these are Church Stowe which is located 7 km to the north and Paulerspury which is 5 km to the south. A stone female head, that mixes Celtic and Roman styles, was found on Watling Street outside the town and was given to the British Museum in 1903.
Lactodurum was surrounded by a wall that was strengthened at several points by brick towers. Substantial remains of one of these towers could be seen until the 1960s, when it was demolished to make way for a telephone exchange. The wall was also surrounded by a ditch part of which became the Mill Leat on the east side of the town.
The modern day St Lawrence's Church in Towcester is thought to occupy the site of a large Roman civic building, possibly a temple. Small fragments of Roman pavement can be seen next to the church's boiler room. It is also thought that a Roman pillar is in the garden of one of the houses along Watling Street.
The Saxon period and Medieval age
When the Romans left in the 5th century, the area was settled by Saxons. In the 9th century, the Watling Street became the frontier between the kingdom of Wessex and Danelaw, and thus Towcester became a frontier town . Edward the Elder fortified Towcester in 917. In the 11th century, the Normans built a motte and bailey castle on the site. Bury Mount are the remains of the fortification and is a scheduled Ancient Monument. It was renovated in 2008 with an access ramp added and explanatory plaques added.
Georgian and Victorian periods
In the 18th and early 19th centuries, in the heyday of the stagecoach and the mail coach, the Watling Street became a major coaching road between London and Holyhead, and Towcester flourished, becoming a major stopping point. Many coaching inns and stabling facilities were provided for travellers in Towcester, many of which remain.
The coaching trade came to an abrupt halt in September 1838 when the London and Birmingham Railway was opened, which bypassed Towcester and passed through Blisworth, barely four miles away but enough to result in Towcester quickly reverting to being a quiet market town. By 1866 however, Towcester was linked to the national rail network by the first of several routes which came together to form the Stratford and Midland Junction Railway, known as the "SMJ". Eventually, from Towcester railway station it was possible to travel four different ways out of the town: to Blisworth (opened May 1866); to Banbury (opened June 1872); to Stratford-upon-Avon (opened July 1873); and finally Olney (for access to Bedford, opened December 1892). The latter line however was an early casualty, closing to passengers in March 1893 although it continued to be used by race specials up until the outbreak of World War II. The Banbury line closed to passengers in July 1951 and the rest in April 1952. Goods traffic lingered on until final axing in February 1964 as part of the Beeching cuts. The site of Towcester railway station is now a Tesco supermarket.
20th century and beyond
The motor age brought new life to the town. Although now bypassed by the A43, the A5 trunk traffic still passes directly through the historic market town centre causing traffic jams at some times of the day. The resulting pollution has led to the town centre being designated an Air quality management area. An A5 north-south bypass is likely with plans for expansion of the town being planned by the West Northamptonshire Development Corporation.