The jurisdiction of the High Sheriff includes all parts of the ancient county of Buckinghamshire, including Milton Keynes. This is described as ceremonial Buckinghamshire.

Buckinghamshire County Council was created in 1889. The county boundaries remained unchanged until the mid 20th Century: in 1974 Slough and Eton were transferred to Berkshire and in 1997 Milton Keynes was made a separate authority.

In the 18th and 19th Centuries, Assize courts were held in Aylesbury and Buckingham, but in 1849 the assizes were moved permanently to Aylesbury and the Judges' Lodgings were built in the middle of the town to accommodate the High Court Judges who travelled from London. In 1970 the Assizes were discontinued and the Judges' Lodgings are now used by the County Council and the High Sheriff for official occasions.