Thetford is a market town and civil parish in the Breckland District of Norfolk, England.

Roger Bigod founded the Cluniac Priory of St Mary in 1104, which became the largest and most important religious institution in Thetford.

After World War II, Thetford became an "overspill town", taking people from London, as a result of which its population increased substantially.

The site was an important crossing of the River Little Ouse, so one possibility is that the settlement drew its name from the Anglo-Saxon Theodford or people's ford.

[6] During the Saxon period it was the principal centre of the eastern Heptarchy and a regular battle site between locals and the Viking invaders.

[4] The town greatly prospered during the reign of Edward the Confessor (1042–1066), and at one point there were 944 free Burgesses living in Thetford.

[7] The Domesday Book of 1086 estimated the population of Thetford to have grown to between 4000 and 4500 people, which would have been the sixth largest town in Britain at the time.

The priory grew rapidly, with an influx of monks from Lewes, and in 1107 it was moved to a larger site on the other side of the river where the ruins remain today.

[12] In 1373, John of Gaunt, the Duke of Lancaster, was responsible for altering the administrative makeup of the town, promoting the mayor to its most important official, subjecting the bailiff and the coroner to report to him.

Thetford had its own coroner, courts and legal officials, without depending on those for the counties of Norfolk and Suffolk.

[13] Henry VIII sent Anne Boleyn's father, Thomas, as part of a Commission to assess Thetford in 1527.

A formal complaint was raised by the mayors and burgesses to Thomas Cromwell in 1539, arguing that many of the town's inhabitants would fall into extreme poverty because their livelihoods depended on pilgrims visiting Thetford.

Thetford Priory was closed down in 1540 and fell into the possession of Thomas Howard, 3rd Duke of Norfolk.

[15] In 1819 there was a local desire to develop Thetford into a spa town modelled on Bath, Cheltenham and Harrogate.

Locally in the wooded and sand like areas,[clarification needed] the trial tests of the first tank took place in total secrecy in early 1915.

[21] To the southeast of Thetford is Nunnery Lakes Nature Reserve, covering about 200 acres, with breckland heath, woodland, fen and open water habitats and 2 kilometres (1.2 mi) of paths.

[17] Thetford was the headquarters of Tulip International, large-scale manufacturers of bacon, beef and pork.

[28] The Black Horse public house dates from the mid 18th century, and is grade II listed.

It contains replicas of the Thetford Hoard and has numerous displays about flinting, rabbit warrens and wildlife.

[32] The external scenes for the BBC TV series Dad's Army were filmed in and around the town, with Thetford's flint buildings doubling for Walmington-on-Sea.

The construction of the second Thetford bypass resulted in five of the course holes being lost and having to be re-fashioned by Cameron Sinclair and Donald Steel.

[44] The station building was designed in a Neo-Jacobean style and constructed using local Breckland flint; it was extended in 1889.