The High Sheriff of Buckinghamshire, in common with other counties, was originally the King's representative on taxation upholding the law in Saxon times. The word Sheriff evolved from 'shire-reeve'.
Sheriff is the oldest secular office under the Crown. Formerly the sheriff was the principal law enforcement officer in the county but over the centuries most of the responsibilities associated with the post have been transferred elsewhere or are now defunct, so that its functions are now largely ceremonial. Under the provisions of the Local Government Act 1972, on 1 April 1974 the office previously known as Sheriff was retitled High Sheriff.
The title of sheriff is therefore much older than the other Crown appointment, the Lord Lieutenant of Buckinghamshire, which came about in 1535.
Unlike the Lord Lieutenant of Buckinghamshire, which is generally held from appointment until the holder's death or incapacity, the title of High Sheriff is appointed or reappointed annually. The High Sheriff is assisted by an Under-Sheriff of Buckinghamshire.
As with the Lord Lieutenant, the purview of the High Sheriff includes both unitary authorities: Buckinghamshire Council(for the south and centre of the county) and Milton Keynes City Council (for the north of the county).