Treorchy (Welsh: Treorci) is a village, although it used to be and still has characteristics of a town, in the county borough (or principal area) of Rhondda Cynon Taf, Wales, lying in the Rhondda Fawr valley. Treorchy is also one of the 16 communities (or civil parishes) of the Rhondda, taking in the near villages of Cwmparc and Ynyswen. Its population in the UK census of 2011 was 7,694.
Prior to industrialisation the tithe maps of the area show an unpopulated area of scattered farmhouses, such as Abergorchwy, Tile-du, and Glyn Coli. The area was predominantly meadows, pastures and woodland and farmed by tenant farmers. The discovery of coal in the Rhondda Valley transformed the locality and within the decades after 1851 Treorchy became a densely populated industrial town. The town grew around the coal mining industry during the late nineteenth and early twentieth century, but by the end of the twentieth century all the local pits had closed, creating an economic downturn in the community.
The Treorchy Male Choir was originally formed in 1883.
The first three maps are provided by A Vision of Britain through Time
These maps were found on Wikimedia Commons
These maps of Glamorgan post-1974 were found on another site and are very useful for sorting out the up-to-date geography of the area