A new level of local government in England and Wales, created in the reorganization of 1974. Scotland and Northern Ireland were also reorganized at the same time, but in different systems.

Before 1974 each County had its own local administration. These functions were removed from the County level and invested in the newly-formed administrative counties. However, in most cases the administrative county's authority coincided closely with the boundaries of a County: for example Norfolk, Suffolk, Cornwall.

In other cases the administrative county covered several Counties, as with "Cambridgeshire", which included both Cambridgeshire and the Isle of Ely as well as Huntingdonshire and the Soke of Peterborough. The administrative county of "Avon" was partly in Gloucestershire and partly in Somersetshire.

Some of the larger Counties were covered by more than one authority, such as Sussex and Yorkshire. The largest cities were grouped into "metropolitan counties", such as Merseyside and Greater Manchester.

There has since (1996+) been another reorganization, and numerous new administrative authorities have been created, primarily for the larger towns, separate from the surrounding administrative county. But Berkshire, for example, is now partly under the administrative county of "Oxfordshire" and partly divided among small unitary regions, i.e. with no further level below them.

The subtle point I am trying to belabour is that an administrative county is a kind of government, but a County is a kind of region. England has been divided into its 39 Counties since Anglo-Saxon times, and Yorkshire and Sussex and Rutland and the rest are places. You can not abolish a place very easily. The County of Yorkshire has existed continuously up to the present day, through 1974 and beyond, unchanged.

There is no government of England. Until very recently there was no government of Scotland or of Wales. This did not mean there are no such places as England, Scotland, or Wales, meaning that there was no level of government covering precisely their geographical area. So it is with Yorkshire: the place currently does not have a single government that governs Yorkshire and nothing else; but it's still there with all its dales and moors and industrial cities.

These artificial entities were never popular and have also been referred to as keg counties, in allusion to the horridness and fakeness of keg beer.

The term 'administrative county' actually came into use in 1889 for a few special cases. The 1974 reform generalized it to the whole of England. In 1889 County Councils were created, and the principal functions of local government were invested in these new councils, where hitherto they had been held by a patchwork quilt of mediaeval instutions like parishes, counties corporate, sokes, and whatnot. Mainly, each County got its own County Council. But several of the biggest ones were administratively divided between their traditional parts.

Lincolnshire was administered as its three parts of Lindsey, Kesteven, and Holland. Yorkshire was administered as its three ridings, and Sussex and Suffolk were administered as East Sussex and West Sussex, East Suffolk and West Suffolk. These subdivisions with their own county councils were referred to as administrative counties.