Only the grand river front survives of Newport Castle. The present castle was probably established in the mid to late fourteenth century, replacing an earlier castle about 1.0km to the south-west on the hill near St Woolos' church, now the Cathedral. The castle was the administrative centre of the eponymous lordship. Significant work was carried out in 1405, at the height of the Glyndwr revolt, and the castle was extensively remodelled in the period between 1430 and 1445. The castle was maintained into the seventeenth century, but was ruinous by the eighteenth. The surviving buildings were used as a brewery in the nineteenth century, whilst the remainder was gradually demolished. In the twentieth century the castle was conserved and consolidated, although a road was built across the western part in 1970.

The earlier castle, first mentioned in 1172, probably lay at ST3046587428 where the Ordnance Survey 1st edition 1:500 map of 1885 shows a cairn (see Archaeologia Cambrensis 5th series II (1885), 261-2). The present castle lies on the riverfront at the northern edge of the medieval borough. It consisted of a walled and moated sub-rectangular court roughly 57m north-south by 62m. The main gate opened onto the town, near the head of the Usk Bridge, and a second led north into the 'Castle Garden'. The magnificent riverfront has towers at the centre and at either end. The end towers are polygonal, rising from spurred bases, and the centre tower is rectangular with projecting turrets flanking the arch of a water gate or dock. It houses a sumptuous series of apartments with a great hall to the north, a magnificent vaulted audience chamber above the water gate and three tiers of chambers in the end towers. There were kitchens in the southern area.

Source: Knight in the Monmouthshire Antiquary 7 (1991), 17-42

John Wiles, RCAHMW, 15 February 2008