South Wales (Welsh: De Cymru) is an area of Wales bordered by England and the Bristol Channel to the east and south, and Mid Wales and West Wales to the north and west.
The exact extent of South Wales is loosely defined, but it is generally considered to be the area surrounding the M4 Motorway, including the counties of Glamorganshire and Monmouthshire and extending westwards to include south Carmarthenshire and south Pembrokeshire. In the western extent local people would probably recognise that they lived in both South Wales and in West Wales - there is considerable overlap in these somewhat articificial boundaries. The northern border is particularly ill-defined, but the A40 may be a good approximation whilst others would use the more southerly Heads of the Valleys Road as the clearly identifiable boundary.
South Wales incorporates the capital city of Cardiff and the city of Newport. The city of Swansea is also sometimes included in the area. The area also includes the South Wales Valleys and the Brecon Beacons National Park.