I.

Introduction

Merthyr Tydfil (Welsh, Merthyr Tudful), county borough and unitary authority, South Wales, bounded on the north by the county of Powys, on the east and south by the county borough of Caerphilly, and on the west and south by the county borough of Rhondda Cynon Taff. The county borough came into existence as a unitary authority on April 1, 1996, 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. It comprises the district of Merthyr Tydfil from the north-east of the former county of Mid Glamorgan. Before 1974, when Mid Glamorgan was created under the local government reorganization implemented in that year, the territory covered by the county borough was part of the county of Glamorgan. It has an area of 111 sq km (43 sq mi).