Grade I listed buildings in Merthyr Tydfil County Borough
Merthyr Tydfil County Borough is located in the historic county of Glamorgan in Wales and takes its name from its largest town. The county borough covers an area of and had a population of approximately 60,400 in 2020. 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. Listing was begun by a provision in the Town and Country Planning Act 1947. Once a building is listed, strict limitations are imposed on the modifications allowed  to its structure or fittings and alterations require listed building consent. In Wales, authority for listing or delisting, under the Planning (Listed Buildings and Conservation Areas) Act 1990, rests with the Welsh Ministers, though these decisions are based on the recommendations of Cadw. There are around 30,000 listed buildings in Wales and these are categorised into three grades: Grade I (one), II* (two star) and II (two). The highest is Grade I which denotes "buildings of exceptional interest" and makes up fewer than two per cent of the total number of listed buildings in Wales. Grade I listed buildings in