Ton Farmhouse, Llangybi

Tregrug Castle (Welsh: Castell Tregrug; Welsh pronunciation: [ˈkastɛɬ trɛˈɡriːɡ]) or Llangibby Castle is a ruin in Monmouthshire, Wales, located about 1 mile (1.5 km) to the north of the village of Llangybi, close to the settlement of Tregrug. The castle appears to have superseded an earlier Norman motte-and-bailey castle, which is first mentioned in records dating from 1262. Surrounded by dense woodland, on the top of a ridge, the present remains include a large, nearly rectangular walled enclosure, about 164 m (180 yards) by 78 m (85 yards), surrounded by ditches - the size of the bailey makes it the largest single-enclosure castle in England and Wales. The bailey is entered through a gatehouse, to the left of which stands a large stone tower, known as the 'Lord's Tower'. Recent archaeological thinking suggests that the castle's main function may have been recreational rather than defensive; it was probably built as a hunting lodge, with accompanying gardens in the style of a late medieval ‘pleasance’. The castle had fallen into disuse by the 16th century but was refortified and garrisoned during the English Civil War. Slighted at the war's end, it was subsequently redeveloped as a landscape garden feature, to complement a new house, New Llangibby Castle, which was built in the grounds at the very end of the 17th century.

Llangybi (also spelled Llangibby) is a village and community in Monmouthshire, in southeast Wales, in the United Kingdom. It is located 3 miles (4.8 km) south of the town of Usk and 5 miles (8 km) north of Caerleon, in the valley of the River Usk. In 2011 the village itself had a population of 444, with a nearly equal number living in its outlying areas, among them the settlement of Tregrug, near the ruins of a medieval castle.

New House Farm, Llangybi, Monmouthshire is a substantial farmhouse dating from c.1700. It has been little altered since the date of its construction. It is a Grade II* listed building.

The White Hart Inn, Llangybi, Monmouthshire is a public house dating from the early 17th century. Located at a crossroads in the centre of the village, it is a Grade II* listed building.

The Church of St Cybi, Llangybi, Monmouthshire is a parish church with its origins in the 13th or 14th century. Refurbished in the 15th century, the church was restored in 1909–10. The interior has a notable collection of medieval wall paintings, in particular a Christ of the Trades, dating from c.1460. The church is an active parish church and part of the recently-formed Heart of Monmouthshire Ministry Area. It is a Grade II* listed building and the architectural writer John Newman, recording the church in the Buildings of Wales series, described it as "one of the most interesting in the Usk Valley."

Berllan-deg, Llanhennock, Monmouthshire is a country house dating from the mid-17th century. A rare survival of a remarkably unaltered hall house, Berllan-deg is a Grade II* listed building.

Tredunnock (Welsh: Tredynog) is a small village in Monmouthshire, south east Wales, in the United Kingdom. Tredunnock is located four miles (6.4 km) northeast of Caerleon and four miles south of Usk.

The Church of St Andrew, Tredunnock, Monmouthshire is a parish church with its origins in the 12th or 13th century. A Grade II* listed building, the church remains an active parish church.

Glen Usk, Llanhennock, Monmouthshire is a country house dating from 1820. It was built for Sir Digby Mackworth, Bt. in the Neoclassical style. The house is Grade II* listed and the adjoining temple, and other associated structures, have their own Grade II listings. The gardens are included on the Cadw/ICOMOS Register of Parks and Gardens of Special Historic Interest in Wales.

Newbridge-on-Usk (Welsh: Pontnewydd ar Wysg) is a hamlet in the village and parish of Tredunnock, near Usk, Monmouthshire, south east Wales, in the United Kingdom.

New Bridge crosses the River Usk at Newbridge-on-Usk between Usk and Caerleon. The bridge carries the B4236. It was constructed in 1779, probably by William Edwards, a prominent civil engineer of Pontypridd, or by a member of his bridge-building dynasty. The bridge has Grade II* listed building status.

The Usk Inlier is a domed outcrop of rock strata of Silurian age in Monmouthshire in south-eastern Wales. It is located in the countryside between the towns of Caerleon and Pontypool and the village of Raglan. The longer axis of the dome or 'pericline', often referred to as the Usk Anticline, is aligned north–south. The inlier is largely surrounded by a sequence of Old Red Sandstone rocks of Devonian age, though both these and the Silurian rocks are largely obscured by superficial deposits.