I.

Introduction

Caerphilly (Welsh, Caerffili), county borough and unitary authority, South Wales, bounded on the north by the county of Powys, on the north-east by the county borough of Blaenau Gwent, on the east by the county borough of Torfaen, on the south by the county of Cardiff, on the west by the county borough of Rhondda Cynon Taff, and on the north-west by the county borough of Merthyr Tydfil. The territory occupied by the county borough was part of the county of Glamorganshire until 1974 when, under the reorganization of local government that year, it was divided into the districts of Rhymney Valley and Islwyn in the new counties of Mid Glamorgan and Gwent respectively. On April 1, 1996, the two districts were combined to form the county borough of Caerphilly. The change was implemented under the provisions of the Local Government Act 1994, which changed the structure of local administration in Wales from a two-tier system of county and district councils to a single-tier system of unitary authorities. Caerphilly county borough has an area of 279 sq km (108 sq mi).