Refortified during the English Civil War, it was eventually slighted, i.e. deliberately destroyed, after being captured by Parliamentary forces after a long siege.

The site was subsequently left relatively undeveloped, and the limited remains of the castle walls and the considerable earthworks are now open to the public.

[3] The wooden castle was built in the north-east corner of the town, taking advantage of the old Anglo-Saxon ramparts, with the motte close to the river overlooking the ford, and required substantial demolition work to make room for the new motte-and-bailey structure.

[3] Wallingford Castle was now the most easterly stronghold of the Empress's faction – it was either the closest base to London, or the first in line to be attacked by Stephen's forces, depending on one's perspective.

[12] Brien had brought in considerable supplies – contemporaries believed the castle could survive a siege for several years if need be – and Stephen changed his mind, putting up two counter-castles to contain Wallingford along the road to Bristol, before continuing west.

[14] The civil war between Stephen and Matilda rapidly descended into an attritional campaign, in which castles like Wallingford played a critical role in efforts by both sides to secure the Thames Valley.

John made extensive use of Wallingford Castle during the First Barons' War between 1215 and 1216, reinforcing the fortifications and mobilising a substantial garrison to protect it.

[3] Edward II gave Wallingford Castle first to his royal favourite, Piers Gaveston, and then to his young wife, Isabella of France, with large sums still being spent on the property.

Edward continued to use the castle as a royal prison for holding his enemies, until his own fall from power in 1326; Isabella, who overthrew her husband, then used it as an early headquarters following her invasion of England.

[23] Wallingford Castle played little role in the Wars of the Roses and after Henry VIII used it for a final time in 1518 it appears to have fallen into disuse as a royal residence.

The antiquarian John Leland described the castle in 1540 as being "nowe sore yn ruine, and for the most part defaced", although the jail continued in use throughout the period, albeit still suffering from many escapee inmates.

Held by various nobles from 1600 onwards, it returned to the crown under Charles I, who gave it to Queen Henrietta Maria, but by then the castle was only really valuable for the surrounding meadow land and fisheries.

[27] The mansion, abandoned due to rising costs, was demolished in 1972, allowing Wallingford Castle to be declared a scheduled monument as well as a Grade I listed building.

An archaeological research project run by Leicester University conducted a sequence of excavations between 2002 and 2010, aiming to better understand the historical transition from the Anglo-Saxon town of Wallingford and the burgh, to the period of the Norman castle.