The Roman marching camp at Blaen Cwm Bach is defined by intermitant stretches of bank and ditch describing an elongated, round-angled rectangle, about 880m ENE-WSW by 300m, with a centrally placed entrance with titulum on the western side.
Small scale excavations were carried out in 1969-74; in 1969 -70 an area of the northern sector of the western rampart was examined, and a 'cooking trench', 2.3m by 0.5-0.8m, set at right-angles to the rampart, and a possible oven were recorded. An area immediately to the north, examined in 1972, showed traces of possible hearths, as did an area within the camp's south-western angle, explored in 1974. The rampart appears to have had an inner revetment of stone & clay, whilst the ditch on the western side had been cut to the bedrock, with a tool-cut channel along its base.
The relationship of the camp with the defended enclosure found within its western angle (Nprn307217), is uncertain (see also Carn Caca camp (Nprn304777).