Donnington Castle, which is in the care of English Heritage, was built by its original owner, Richard Abberbury the Elder, under a licence granted by Richard II in 1386. The surviving castle gatehouse dates from this time. The castle was subsequently bought by Thomas Chaucer, the son of the poet Geoffrey Chaucer, as a residence for his daughter Alice, who later became Duchess of Suffolk. This family later fell out with the Tudor monarchs, and the castle became a Royal property. Both King Henry VIII and Queen Elizabeth I visited Donnington Castle, in 1539 and 1568 respectively.
The castle was originally built in a rectangular form, with a curtain wall cornered by four round towers, two square wall towers, and a substantial gatehouse, constructed around a courtyard. The courtyard buildings were probably of timber construction and possibly included a hall, kitchen, and guest lodgings.
By the time the English Civil War broke out in 1643, the castle was owned by the Parliamentarian John Packer family but after the First Battle of Newbury it was taken for the King, Charles I, and held by Sir John Boys. They quickly built defences on the slopes of the hill in a star shape. The projections were for gun emplacements, the scarps and platforms of which survive today. Despite being besieged for most of the war, it had to be relieved by the King on two occasions, the castle succeeded in guarding the major routeways from London to the West Country and Oxford to Southampton. During the Second Battle of Newbury, the castle was able to hold off the Parliamentary attackers. Finally, after an eighteen month siege, the garrison, after obtaining the Kings permission, abandoned the damaged castle and were allowed to rejoin Royalist forces in Wallingford.
In 1646 Parliament voted to demolish the castle leaving only the gatehouse remaining, which was then restored to John Packer. All that remains of the castle today is the substantial four towered gatehouse, and the surrounding earthworks.
The castle is now in the care of English Heritage and is a scheduled ancient monument number 233041. The gatehouse is two storeys high and roofed at battlement level. The external walls of the castle have been rebuilt to a height of 0.5 metres to indicate the original layout. The temporary Civil War works remain for the most part as scarps averaging 1.7m high.