This list shows towns or cities which held county functions at various points in time.
Following the Norman invasion of Wales, the Cambro-Normans created the historic shire system (also known as ancient counties).
The 1535 Laws in Wales Act established the historic counties in English law, but in Wales they were later replaced with eight preserved counties for ceremonial purposes and the twenty two principal areas are used for administrative purposes.
(Note: not all headquarters are or were called County Halls or Shire Halls e.g.: Cumbria County Council's HQ up until 2016 was called The Courts and has since moved to Cumbria House.)
The follow lists the location of the administration of each of the 31 local authorities in the Republic of Ireland, with 26 of the traditional counties.