Page "History of Oxfordshire" Paragraph 6

The Vale of the White Horse district and parts of the South Oxfordshire administrative district south of the River Thames were historically part of Berkshire, but were added to the administrative county of Oxfordshire in 1974.

Conversely, the Caversham area of Reading now belongs to Berkshire but was historically part of Oxfordshire as was the parish of Stokenchurch, now in administrative Buckinghamshire.