The museum is in a wing of Great Castle House, a listed building on the Monmouth Heritage Trail.

[1][2] It is within the 19th-century wing which extends from Great Castle House (pictured), a 17th-century, grade I listed building just northwest of Agincourt Square.

[3][4] Great Castle House is one of 24 blue plaque buildings on the Monmouth Heritage Trail.

[5][6] In 1673, it was constructed from the ruins of Monmouth Castle by the 1st Duke of Beaufort, then the 3rd Marquess of Worcester, as a town house while his other homes were being rebuilt.

[4][8] Described by BBC Worldwide's Lonely Planet as "a labour of love squeezed into a cupboard-sized space," the Castle and Regimental Museum was established in 1989 by the Duke of Gloucester.

[3] The Monmouth Regimental Museum (link to website below) is staffed by volunteers and has free admission.

[14] The displays at the museum cover a number of subjects, including the Militia structure and the Dukes of Beaufort.

[3] Objects include a regimental drum from the late 19th century, a water testing kit, and a canned cake ration from World War II.

[3] One mediaeval artefact displayed in the museum is a fireless cooking pot that was discovered on Castle Hill (link to the archaeological find below).

[3] In front of the building, the museum displays a number of larger pieces of military equipment, including a British armoured fighting vehicle (pictured above).