Grade II* listed buildings in Merthyr Tydfil County Borough

Two viaducts constructed as part of the Brecon and Merthyr Railway both straddle the borders of neighbouring communities so have separate designations for each of these locations.

The previous fifty years had seen the establishment of four major ironworks in the area, Dowlais, Plymouth, Cyfarthfa and Penydarren,[13] and the Grade II* listed architecture of the region reflects the growth of this industry and transport network associated with it.

The oldest structure, a bridge built in 1793, had a dual purpose as it carried a tramway and aqueducts powering the Cyfarthfa Ironworks.

[14] The growth of iron foundries in Merthyr Tydfil led to the building of the Glamorganshire Canal (1791–1795) connecting the industry to the docks at Cardiff.

[13] Within a decade the Merthyr Tramroad, a 15.3 km (9.5 miles) route linking the Dowlais and Penydarren works to Abercynon, was built to bypass the upper section of the canal.