The architectural historian John Newman, in his Gwent/Monmouthshire volume of The Buildings of Wales series described the court as "the most impressive and richly decorated house of around 1600 in Monmouthshire".

The building was given its present appearance by a substantial enlargement and re-casing of circa 1600 by Rhys Morgan, of the family of the original owners.

Nicholas Arnold was a noted horse-breeder as well as Member of Parliament for Monmouthshire and was responsible for the construction of the Stable Block at Llanvihangel.

His religious views and marked intolerance of Catholics, in a county with a strong recusant tradition,[6] made him a controversial figure.

An example was the Jesuit Father David Lewis who was caught by Arnold at St Michael's Church, Llantarnam, held at Llanvihangel, and subsequently executed at Usk in 1679.

[2] The north front is of two storeys and six bays, and is from the Morgan extension of 1599,[2] and later made more symmetrical by Nicholas and John Arnold in the mid and late 17th century.

[12] Further work continued as late as the 20th century; Mrs Matthews adding two huge bay windows to the east front and a "strange Egyptian-style room" to the south in 1905.

Hando recorded the "seventeenth century decorated plaster work ceiling" in the great hall, and the fire-back, dated 1694, which had previously formed a bridge over a nearby stream.

[14] John Newman records the view of the Secretary of the Royal Commission on the Ancient and Historical Monuments of Wales who suggests that some of the plaster ceilings, long considered to be Jacobean, may in fact be careful re-modellings of the early 20th century by the architectural partnership of Bodley and Garner, who were undertaking contemporaneous remodelling at Powis Castle.

[2] On the turn are two early 20th century stained glass windows, depicting Elizabeth I and Charles I and his family, both of whom are traditionally supposed to have visited the court.

The plan is axial, the court at the centre, surrounded by terraces, and with two long avenues of trees, pines to the north and sweet chesnuts to the south.

[5] Near the lake there is a small brick summerhouse, also called the Guardhouse or Garden House, which was originally one of a pair completing a walled enclosure around the court.