Merthyr Tydfil County Borough in the context of "Mid Glamorgan"

The Cardiff Capital Region (CCR; Welsh: Prifddinas-Ranbarth Caerdydd) is a city region in Wales, centred on the capital city of Wales, Cardiff, in the southeast of the country. It is a partnership between the ten local authorities of Blaenau Gwent, Bridgend, Caerphilly, Cardiff, Merthyr Tydfil, Monmouthshire, Newport, Rhondda Cynon Taf, Torfaen, and the Vale of Glamorgan, local businesses in southeast Wales and other organisations. The regional city deal is funded by the UK Government and Welsh Government. The Cardiff Capital Region includes the cities of Cardiff and Newport, and most of the South Wales Valleys, with the region being coterminous with the area defined as South East Wales.

Powys (/ˈpoʊɪs, ˈpaʊɪs/ POH-iss, POW-iss, Welsh: [ˈpou̯ɪs]) is a county and preserved county in Wales. It borders Gwynedd, Denbighshire and Wrexham to the north; the English ceremonial counties of Shropshire and Herefordshire to the east; Monmouthshire, Blaenau Gwent, Merthyr Tydfil, Caerphilly, Rhondda Cynon Taf and Neath Port Talbot to the south; and Carmarthenshire and Ceredigion to the west. The largest settlement is Newtown, and the administrative centre is Llandrindod Wells.

Powys is the largest and most sparsely populated county in Wales, having an area of 5,181 km (2,000 sq mi) and a population of 135,059 in 2024. While largely rural, its towns include Welshpool in the north-east, Newtown in the north-centre, Llandrindod Wells in the south-centre, Brecon in the south, Ystradgynlais in the far south-west, and Machynlleth in the far west. The Welsh language can be spoken by 16.4% of the population. The boundaries of Powys largely follow those of the historic counties of Montgomeryshire, Radnorshire, and Brecknockshire.

Rhondda Cynon Taf (Welsh pronunciation: [ˈr̥ɔnða ˈkənɔn ˈtaːv]; RCT; also spelt as Rhondda Cynon Taff) is a county borough in the south-east of Wales. It consists of five valleys: the Rhondda Fawr, Rhondda Fach, Cynon, Taff (Welsh: Taf) and Ely valleys, plus several towns and villages away from the valleys.

Results from the 2011 census showed 19.1% of its 234,410 residents self-identified as having some ability in the use of the Welsh language. The county borough borders Merthyr Tydfil County Borough and Caerphilly County Borough to the east, Cardiff and the Vale of Glamorgan to the south, Bridgend County Borough and Neath Port Talbot to the west and Powys to the north. Its principal towns are - Aberdare, Llantrisant with Talbot Green and Pontypridd, with other key settlements/towns being - Maerdy, Ferndale, Hirwaun, Llanharan, Mountain Ash, Porth, Tonypandy, Tonyrefail and Treorchy.