The administrative counties did not exist prior to 1889, see historic counties of England for the history of the English counties before then.
In 1888 the government, led by the Tory prime minister Lord Salisbury established county councils throughout England and Wales, covering areas known as administrative counties. Many larger towns and cities were given the status of county borough, with similar powers and independent of county council control. Under the Act, each county borough was an "administrative county of itself".
Additionally there was a County of London which covered the area today known as Inner London. The Isle of Wight was previously administered as part of Hampshire but became its own administrative county in 1890.
In 1894 a uniform two-tier system was established outside the county boroughs and London, with subdivisions of the administrative counties called urban districts, rural districts and municipal boroughs. The structure was complete once the County of London was divided into metropolitan boroughs in 1900.