An urban district in the western parliamentary division of Monmouthshire, England, 21 m. N.W. of Newport on the Great Western, London & North-Western and Rhymney railways. Pop. (1891) 17,31 2; (1901) 20,99 4. It lies near the head of the valley of the river Ebbw, at an elevation of nearly moo ft., in a wild and mountainous mining district, which contains large collieries and important iron and steel works.