It is located approximately one mile east of Monmouth, on the eastern side of the River Wye and adjacent to the border with the Forest of Dean and England.

[2] The members of the Kymin Club were drawn from "the principal Gentlemen of Monmouth and its vicinity", and met each week "for the purpose of dining together, and spending the day in a social and friendly manner".

[1] The Roundhouse was constructed to provide "security from the inclemency of the weather"[1] and the subscription list for funding was headed by the local landowner, Henry Somerset, 5th Duke of Beaufort, and eight Members of Parliament.

[3] The building was sited to take advantage of the views and the Monmouth antiquarian and publisher Charles Heath recorded in his 1807 history; Descriptive Account of the Kymin Pavilion and Beaulieu Grove with their various views; also a description of the Naval Temple that ten counties could be seen from the Roundhouse; (Gloucestershire, Monmouthshire, Glamorganshire, Breconshire, Montgomeryshire, Worcestershire, Herefordshire, Radnorshire, Shropshire and Somerset).

The club members wanted a venue suitable for their regular meetings, dining and events and the building was designed with kitchens on the ground floor and a banqueting room above.

[8] Staying in Monmouth for just a couple of days, Nelson visited the Naval Temple and the Roundhouse on Kymin Hill, where he breakfasted and admired the views.

[9] At that time, the figure of Britannia had been lost, as had the two naval seascape paintings depicting The Battle of the Nile and The Standard of Great Britain Triumphant.

According to the historian Peter Borsay, the monument's design, and its location overlooking the border between England and Wales, were symbolic of the formation of Great Britain.

In building the temple, Monmouth staked its own claim to be the centre of British identity as the birthplace of King Henry V, of whom a statue was placed on the Shire Hall in 1792.

Within two years of the battle of Waterloo in 1815 the name of the town's market place had been changed to Agincourt Square "in order to celebrate a victory of Henry V's that seemed as famous as Wellington's.