Wallingford (ˈwɒlɪŋfərd) is a historic market town and civil parish on the River Thames in Oxfordshire, England, north of Reading, south of Oxford and north west of Henley-on-Thames. Although belonging to the historic county of Berkshire, it is within the ceremonial county of Oxfordshire for administrative purposes (since 1974) as a result of the 1972 Local Government Act. The population was 11,600 at the 2011 census.
The town has played an important role in English history starting with the surrender of Stigand to William the Conqueror in 1066, which led to his taking the throne and the creation of Wallingford Castle. The castle and the town enjoyed royal status and flourished for much of the Middle Ages. The Treaty of Wallingford, which ended a civil war known as The Anarchy between King Stephen and Empress Matilda, was signed there. The town then entered a period of decline after the arrival of the Black Death and falling out of favour with the Tudor monarchs b