The South Wales Mountain Sheep, which is also sometimes called a Nelson or a Glamorgan Welsh, is the largest of the Welsh Mountain breeds. It is believed to be of the same primitive ancestry as the Welsh Mountain Sheep, but for many years it has been self-contained and bred to a definite local type, the characteristics of which have become so pronounced as to make it distinct from any other hill breed. It is found chiefly in the hill districts of Glamorgan, Gwent and South of the Brecon Beacons.