England and Wales

The term was introduced for England and Wales by the Local Government Act 1888, which created county councils for various areas, and called them administrative counties to distinguish them from the continuing statutory counties.

In England and Wales the legislation was repealed in 1974, and entities called 'metropolitan and non-metropolitan counties' in England and 'counties' in Wales were introduced in their place. Though strictly inaccurate,^{[citation needed]} these are often called 'administrative counties' to distinguish them from both the historic counties, and the ceremonial counties.

Scotland

For local government purposes Scottish counties were replaced in 1975 with a system of regions and island council areas.

Ireland

The Local Government (Ireland) Act 1898 created administrative counties in Ireland on the same model that had been used in England and Wales.

In Northern Ireland the administrative counties were replaced by a system of 26 districts on 1 October 1973. Section 131 of the Local Government Act (Northern Ireland) 1972 stated that "every county and every county borough shall cease to be an administrative area for local government purposes".^[1] The areas of the former administrative counties (and county boroughs) remain in use for Lieutenancy purposes, being defined as the areas used "for local government purposes immediately before 1 October 1973, subject to any subsequent definition of their boundaries …".^[2]

In the Republic of Ireland the legislation that created them remained in force until 1 January 2002, when they were renamed as counties under the Local Government Act 2001.^[3] The term administrative county is retained by the Placenames Database of Ireland to distinguish the modern counties in Dublin of Dún Laoghaire–Rathdown, Fingal and South Dublin from the traditional counties, which include County Dublin.^[4][5]