Penydarren Park is laid out on part of the estate gardens of Penydarren House, the very first of the ironmaster's mansions built in Merthyr (NPRN: 19696). The house itself had been constructed in 1786 who owned the Penydarren Ironworks and was located on the site of earlier Roman occupation (NPRN: 301352). During the nineteenth century, largely because of the absence of recreational facilities in the town, Penydarren Park was used for the everyday leisure of the working people of Merthyr. Equally, because of its then relatively secluded landscaping, it was also gained a reputation for being a place to pick up prostitutes. Towards the end of the nineteenth century, Penydarren was developed into a sporting arena with an athletics track and a triangular cycling track. This was lost with the advent of rugby football and association football at Penydarren in the first decade of the twentieth century. Home to Merthyr Tydfil's Northern Union (Rugby League) side from 1907-1910 and subsequently Merthyr Town F.C., Penydarren was transformed into a football arena complete with banked terracing and grandstands. 

The first football match to be played at Penydarren Park took place on 28 March 1908 when Treharris faced Aberdare in the South Wales Cup. Merthyr Town were then formed in the summer of 1908 and moved into Penydarren Park, playing their first competitive match in the South Wales League on 4 September 1908 for the visit of Swansea. On 29 April 1909, Manchester City visited Penydarren Park for a friendly match, played in front of 7,000 spectators.In the 1930s, the stadium was also used for greyhound racing and this necessitated the construction of a running track around the outside of the field. Today, the stadium retains much of its earlier appearance with open terracing along the northern and eastern sides of the ground and two grandstands (one behind the western goal; the other along the southern touchline).

In 2014 a new 3G artificial pitch was installed to allow for all-weather playing and year-round use. The installation of the 3G pitch at Penydarren Park was funded from the Ffos y Fran Community Fund which is jointly administered by Miller Argent Limited and Merthyr Tydfil County Borough Council. The ground has a capacity of 4,500.

Daryl Leeworthy, RCAHMW, 24 October 2011.
Meilyr Powel, RCAHMW, October 2020.

Sources:

'History', merthyrtownfc.co.uk
'Play @ the Park', merthyrtownfc.co.uk