Monmouthshire is a county and principal area of Wales. It borders Torfaen and Newport to the west; Herefordshire and Gloucestershire to the east; and Powys to the north. The largest town is Abergavenny, with the other major towns being Chepstow, Monmouth, and Usk. The county is 850 km2 in extent, with a population of 95,200 as of 2020. The present county was formed under the Local Government (Wales) Act 1994, which came into effect in 1996, and comprises some sixty percent of the historic county. Between 1974 and 1996, the county was known by the ancient title of Gwent, recalling the medieval Welsh kingdom. In his essay on local government in the fifth and final volume of the Gwent County History, Robert McCloy suggests that the governance of "no county in the United Kingdom in the twentieth century was so transformed as that of Monmouthshire".

In the United Kingdom, the term listed building refers to a building or other structure officially designated as being of special architectural, historical, or cultural significance; Grade I structures are those considered to be "buildings of exceptional interest". Listing was begun by a provision in the Town and Country Planning Act 1947. Once listed, strict limitations are imposed on the modifications allowed to a building's structure or fittings. In Wales, the authority for listing under the Planning Act 1990 rests with Cadw.